300 PRC pet loads

[mrcheesemoose]

Didn’t see a thread for 300 PRC load data. I want to collect some good loads people have tried to spare precious powder and primers for us that load 300 PRC.

I’ll start:

78 grains H1000
200 grain eldx
CCI 34s
Federal brass

Gives me pretty solid groups and right around 3000 fps in my 26 in barrel

 

[rustyinbend]

Rifle is a Barrett MRAD w/ 300-PRC Barrel Kit
Lapua 2x brass
Retumbo 77.4
Berger 220 LRHT
Federal GM LR Primers

Velocity 2,878 ft/sec
SD 6.32
ES 24

Dings 2'x2' steel at a mile all day long.

 

[max1840]

Mausingfield
Bartlein - 26" MTU - 1:8.5"
Hornady Brass 1x Fired
CCI250 Primer
RL26 - 75.4
Berger 230 LRHT
CBTO - 2.917
FPS - 2891
SD - 8.2 ES - 23

 

[drifter308]

Tempalar V2
Bartlein 26" 1.25 straight 1:9"
ADG 1X Brass
78.0 H1000
230 Berger OTM
CBTO 2.995
FPS 2,886
SD 2.6 ES 5

 

[yej0001]

Follow

 

[Huskydriver]

78gr retumbo. 26" 1/9

 

[HemiPowrd]

Made it out to the range today. Loaded up 40 rounds with 77.3 gr of H-1000. Loaded long and had to single feed each round.
Bartlein heavy 30" 1:9 twist
Virgin ADG brass
Hornady 230 gr A-tip
77.3 gr H-1000
CCI 200 primers
COL 3.826"
Jump 0.015"

Barrel looks it was still speeding up with 110 rounds down the pipe. Getting around 2865 FPS now. This may not be my final load just yet since I was using virgin brass and speed on the barrel may still be climbing, but I'm thinking it'll at least be close.

Barrel tuner test target. Looks like tuner in position 12 is dead nuts. Two shots at each dot.

 

[Max_The_Phoenix]

Ok looks like I was able to finalize my load today.
Load #1
220 LRHT
Cci 250
77.4gr Retumbo @ 2856fps
SD: 2.4, ES:4

Load #2
220 LRHT
Cci 250
78.6 gr Retumbo @ 2907fps
SD: 9.1, ES:18

Both are making 0.28 MOA 3 shot group at 100 yards.

 

[mrcheesemoose]

Ok looks like I was able to finalize my load today.
Load #1
220 LRHT
Cci 250
77.4gr Retumbo @ 2856fps
SD: 2.4, ES:4

Load #2
220 LRHT
Cci 250
78.6 gr Retumbo @ 2907fps
SD: 9.1, ES:18

Both are making 0.28 MOA 3 shot group at 100 yards.

What’s the barrel?

 

[Max_The_Phoenix]

What’s the barrel?

Bartlein HV 1:9 28" with 250rds

 

[Kickin45]

Ordered a new barrel 2 weeks ago. 1:8tw, 28” for the DT SRSa1.
Talked to the Berger rep Friday (can’t say enough good things about their customer care). He gave me some incredible insights for the 230 & 245 Bergers. I’ve never shot them, but am excited to develop a load for them.
I’ll update here as that load developments.
My goal with the 245’s is 2850-2875fps and single digits.
Your guys info has been incredibly beneficial. Hope I can soon return the favor
Fingers crossed

 

[Jink00]

Didn’t see a thread for 300 PRC load data. I want to collect some good loads people have tried to spare precious powder and primers for us that load 300 PRC.

I’ll start:

78 grains H1000
200 grain eldx
CCI 34s
Federal brass

Gives me pretty solid groups and right around 3000 fps in my 26 in barrel

I just did a load workup for my bergara wilderness hmr 26in barrel. My rifle loved
Adg brass
H1000-79.9 gr (over book no pressure signs)
Wlrm primers
220gr eldx
.042 off lands
3010 fps sd of 7.6
It shot .64 outside to outside on 2 4 shot grps

 

[Kickin45]

I just did a load workup for my bergara wilderness hmr 26in barrel. My rifle loved
Adg brass
H1000-79.9 gr (over book no pressure signs)
Wlrm primers
220gr eldx
.042 off lands
3010 fps sd of 7.6
It shot .64 outside to outside on 2 4 shot grps

What is your OAL?

 

[Jink00]

What is your OAL?

3.580

 

[SaltyDog89]

New to 300 PRC with a new Sig Cross here in 2025! Only about 40 rounds into the new rifle and it's meeting all expectations so far for where I hoped it would as I continue fine tune my first load work up. Also working on improving my reloading skills with it. Strange, I thought there would be more forum discussion for the 300 PRC but maybe I just need to look harder. For the first time with any caliber I'm also doing a "never buy any rounds" thing with it and it's looking great already to be on this path.

Current Load: Sig Cross 24" barrel
H1000; new Lapua Brass; BR CCI primers; Berger Hybrid Target 215 Grain bullets
- Currently settled on '81.20' grain of power; with 2.915" Ojive; 2.260" neck and 3.700" COAL.
- Last read of 10 consecutive shots yields a 11.1 STD (Spread of 33.9 ) and 2,926 fps average
- Grouping right at 1 MOA with 10 shots (1/2 MOA with fewer shots so the shooter does the best that he can here and the variation increases with more rounds of course)
- I have installed an Arken 35x scope so, seeing the target very clearly at 100 yards is of course like it's a foot from the barrel.
- All internal necks dry lubed and run through a 30 cal carbide mandrel for new brass
- So far, all fired rounds so far with RCBS Charge Master 1600 only with its associated power accuracy
- As far as I can tell, I have not seen any signs of tight bolt or case issues with this rifle and the 81.2 change load.
- I must give credit to the Sig Cross; recoil somehow feels right at or a little less that my 308 with this rifle but it could also be too just feeling less in my shoulder with age..

Questions/Comments to anyone familiar here: (In short; how to push for better SD and tighter groups of course?)
- First time use with H1000 powder and it seems darn good; hard to know what powder could be 'better'? I have a 30 cal can but not used yet until I have my initial work up complete and proven repeatable.
- All my future rounds will be using the FX-120i scale for the better accuracy (just got it) so TBD on how that improves STD or not yet...?
- I'm sticking to the MAX 3.700" COL allowed so the rounds fit in the pricy rifle mags. These Berger Hybrid bullets hit my lands at about 3.745" so hard to push beyond 3.700" here with little interest to work up single load rounds. Too bad it's that far off so you kind of have to tune loads right at MAX COL which feels like you leave accuracy on the table.
- Still on 1st round with new brass.. No experience with neck turning and it seems painful so we'll see if I get into that later.
- COST of ownership here (just bullet material) which is interesting:
- $3.05 each first use; $1.35 each new reload which really shows how pricy the brass is

 

[HemiPowrd]

I recently started using Neolube 2 on the inside of the case necks when seating bullets. It cut down my SD significantly.

 

[SaltyDog89]

I started using Neolube 2 about 6 months ago and is now part of my default case prep process for everything I load now. It would be interesting to hear from anyone that thinks this is not wise or can cause issues in some manner?
New on my table to apply to the next rounds loaded:
- Full case length seating die; new micrometer Forster 300 PRC sitting on my desk ideally helps with some of edges of consistency
- I'm not sure on the 81.20 grain powder case fill % with lapua brass but it seemed to land in a stable power charge so I'll stick with it.
- I won't neck bump until 2nd+ brass firings so and will target .003 bump later to see how that improves. We'll also see how that changes my seating depth or not when I do?
- Will pass on neck turning for now.. Yea, controlling brass neck thickness seems to be a big deal with the experts but I'll get to it in due time once I really lock in everything else consistently. Neck spring back and all that is also a known thing but for now it's hard to quantify without running a mandrel through again and feeling differences which may be another thing to worry about at some point later as well.
- Primer Seating: I have old school single Hornady press and my primers they get 'mashed' into bullets per this simple press process. This is another area of concern but I'm not ready to shift from standard whatever seating all the way to perfect seating with a $700 primer seater just yet, but TBD.

 

[Williamtell]

2x fired Lapua brass 2.575" and 0.002 shoulder bump
Grand 77 gr
Fed 215M Match primers
208gr Barnes LRX
.050 off lands
3.693 OAL
2930.5 avg mv
SD 4.4
Spread 14.3
0.54" 5-shot group

Christiansen Arms Mesa Long Range
26" barrel 1:8 twist

 

[Williamtell]

I started using Neolube 2 about 6 months ago and is now part of my default case prep process for everything I load now. It would be interesting to hear from anyone that thinks this is not wise or can cause issues in some manner?

A quick Google search stated;

• Neolube No. 2 is a dry lubricant:
  It's designed for applications where a dry, non-corrosive, and non-freezable lubricant is needed.
  
  
• Colloidal graphite:
  This is the primary lubricant in Neolube No. 2. While effective for certain uses, it might not be ideal for a rifle barrel where consistent lubrication is crucial.
  
  
• Not recommended for threads:
  Neolube No. 2 is explicitly stated not to be used for lubricating threads in areas where temperatures exceed 400°F.
  
  
• Not recommended for oxygen environments:
  Neolube No. 2 is also not recommended for use in oxygen environments.
  
  
• Potential for friction:
  The dry nature of Neolube No. 2 could lead to increased friction in the barrel, which could impact accuracy and potentially damage the barrel over time.

 

[Emerson0311]

V570 77 gr 245 Bergers Rem 9 1/2 LRM 2744fps

 

[Kaldor]

Working on a few for my 300 PRC

77.6gr Retumbo
220 Berger
2890fps
Fed GM215M
Lapua brass
20 thou off lands
30" Bartlein 9 twist
Im sure I could get some more velocity out of this one, but its accurate, and thats all I care about. Ive shot this load with pretty good results at 1000 and 1200 yards.

I do have a 220gr SMK load with Retumbo somewhere, but Ill be damned if I cant find it. Its a "good enough" load for steel on the home range that only goes to 700. And its quite a bit cheaper per squeeze of the trigger and the 220 SMK seems to be alot more available.

Currently working on 200.20x bullets, N570 powder, and a few other things. Got the N570 and 200.20x's cheap'ish, so I figured why not. Also messed about with 185 Juggs and Retumbo, but wasnt really a great combo. Also tried N555 which was really accurate, but topped out in velocity at about 2725 with a 220 SMK for obvious reasons but for steel blasting, they were fine. Might revisit that with some 185s at some point as the N555 does better with lighter bullets. Local shop sells quite a bit of Bergers, so I asked them to order some 245 Bergers for me, but no idea when those will show up.

 

[SaltyDog89]

My initial load up for 215 Bergers with H1000 from a few posts above continues to hold steady but my times between evaluating repeatability is rather long between trials but hopefully that starts to improve over the next few months.
- Brass: I'm still on 1st round with new Lapua brass (200 pieces) so can't bump down shoulders until fired once and at my rate I may not be at that point until the end of this summer.
- H1000: For now sticking with the power I have and it does look like a great power for SD.
- Interesting note on 'time' or barrel cleanliness being a factor:
- Some rounds loaded just a few weeks ago that now seem to have shifted up in speed by about 10-15 fps Average, still with good SD. I didn't clean my barrel between my last few firings. Still a new barrel so I may be seeing some barrel break in mixed in with what happens with barrels not being cleaned after 40 rounds......

 

[SaltyDog89]

How can accuracy get worse with 300 PRC reloads???
- I thought I learned enough proper reloading skills to now be smarter than ever with more and more experience in doing things right! Well, 300 PRC is showing me that I may know just enough to make things worse and clearly I do not have enough learning to improve on anything....

Issue:
- 1st loaded new Lapua brass with 215 grain Bergers with 300 PRC and 81.2 grain H1000 give me a solid sub MOA.
--- My power loads are perfect to basically a single grain of H100 powder with my Auto Trickler V4 setup and my care in tracking that accuracy of the associated medical grade scale.
- 2nd loaded (1st time reuse) Lapua brass with all the same clearly off with about 1.5 MOA
---- Confirmed with new brass fire; followed by reloaded brass fire; then followed by new brass file again to ensure any barrel heating or fouling does not come into play with same wait time between shots.
- 101 stuff done.. I hope good Annealing done; resize (shoulder bump from new brass 2.257" up to 2.263"); cases trimmed to try and be consistent with all at about 2.56"; very goof brass cleaning; BR primers and case neck lube after neck mandrel resize.

So, back to learning mode and what did I miss here for what should have been an improvement?
- Neck resize is different but is the bump up expected to throw shots off that much with COAL with seating depth Ojive measured identical from new brass to resized brass?
- I did not neck turn anything which is a pain to do correctly but I do carefully neck size with the same carbine mandrel? Hard to imagine that much accuracy loss from not neck turning...
- Or, when you use fired brass (better sized to your rifle chamber) are you really needing to re-tune your load again from scratch?

Just looking for any thoughts from anyone that may have seen accuracy loss in 1st time brass reloads and found the detail or two you need to focus on to at least keep things at the same accuracy level (or better) as new fresh brass.

 

[Williamtell]

I don't know what is causing it but i experience similar issues. Mine had alot of fouling. Patches were coming out clean, but was still fouled with carbon and copper. Once I got it truly cleaned my groups shrunk considerably.

 

[Big Timber]

How can accuracy get worse with 300 PRC reloads???
- I thought I learned enough proper reloading skills to now be smarter than ever with more and more experience in doing things right! Well, 300 PRC is showing me that I may know just enough to make things worse and clearly I do not have enough learning to improve on anything....

Issue:
- 1st loaded new Lapua brass with 215 grain Bergers with 300 PRC and 81.2 grain H1000 give me a solid sub MOA.
--- My power loads are perfect to basically a single grain of H100 powder with my Auto Trickler V4 setup and my care in tracking that accuracy of the associated medical grade scale.
- 2nd loaded (1st time reuse) Lapua brass with all the same clearly off with about 1.5 MOA
---- Confirmed with new brass fire; followed by reloaded brass fire; then followed by new brass file again to ensure any barrel heating or fouling does not come into play with same wait time between shots.
- 101 stuff done.. I hope good Annealing done; resize (shoulder bump from new brass 2.257" up to 2.263"); cases trimmed to try and be consistent with all at about 2.56"; very goof brass cleaning; BR primers and case neck lube after neck mandrel resize.

So, back to learning mode and what did I miss here for what should have been an improvement?
- Neck resize is different but is the bump up expected to throw shots off that much with COAL with seating depth Ojive measured identical from new brass to resized brass?
- I did not neck turn anything which is a pain to do correctly but I do carefully neck size with the same carbine mandrel? Hard to imagine that much accuracy loss from not neck turning...
- Or, when you use fired brass (better sized to your rifle chamber) are you really needing to re-tune your load again from scratch?

Just looking for any thoughts from anyone that may have seen accuracy loss in 1st time brass reloads and found the detail or two you need to focus on to at least keep things at the same accuracy level (or better) as new fresh brass.

Do you know if there is a velocity difference between the virgin brass loads and the reloads?

 

[max1840]

How can accuracy get worse with 300 PRC reloads???
- I thought I learned enough proper reloading skills to now be smarter than ever with more and more experience in doing things right! Well, 300 PRC is showing me that I may know just enough to make things worse and clearly I do not have enough learning to improve on anything....

Issue:
- 1st loaded new Lapua brass with 215 grain Bergers with 300 PRC and 81.2 grain H1000 give me a solid sub MOA.
--- My power loads are perfect to basically a single grain of H100 powder with my Auto Trickler V4 setup and my care in tracking that accuracy of the associated medical grade scale.
- 2nd loaded (1st time reuse) Lapua brass with all the same clearly off with about 1.5 MOA
---- Confirmed with new brass fire; followed by reloaded brass fire; then followed by new brass file again to ensure any barrel heating or fouling does not come into play with same wait time between shots.
- 101 stuff done.. I hope good Annealing done; resize (shoulder bump from new brass 2.257" up to 2.263"); cases trimmed to try and be consistent with all at about 2.56"; very goof brass cleaning; BR primers and case neck lube after neck mandrel resize.

So, back to learning mode and what did I miss here for what should have been an improvement?
- Neck resize is different but is the bump up expected to throw shots off that much with COAL with seating depth Ojive measured identical from new brass to resized brass?
- I did not neck turn anything which is a pain to do correctly but I do carefully neck size with the same carbine mandrel? Hard to imagine that much accuracy loss from not neck turning...
- Or, when you use fired brass (better sized to your rifle chamber) are you really needing to re-tune your load again from scratch?

Just looking for any thoughts from anyone that may have seen accuracy loss in 1st time brass reloads and found the detail or two you need to focus on to at least keep things at the same accuracy level (or better) as new fresh brass.

Small changes in components can have a big effect on accuracy/precision. That's the beauty of reloading, we can control those changes to our benefit. There is a case capacity change from new brass to once fired which is why it is suggested to measure case capacity (water) on fired brass as opposed to new. That being said, I suspect a velocity change took you out of your accuracy node.

 

[SaltyDog89]

Thanks for the feedback so far.. I'll be doing my first 1,000 yrd trials with the 300 PRC soon here in July so I'll see how that turns out. But to respond here per comments:
- Reference shoot all on same day in this order:
- 300 PRC load: New lapua brass no trim; BR primers; 81.2 grn H1000; Berger 215 Hybrid Target; seated at ~3.7" COAL (ojive 2.915")
(All reference 5 shots - 100 yrd range - indoor - no wind)
1) NEW BRASS loaded 3/15/25 : 2924 fps - 6.4 STD (first 5 - 30 sec cooling per) easy <MOA)
- all centered with scope
2) 1st Resized loaded 6/19/25 : 2916 fps - 9.8 STD (next 5 - 30 sec cooling per) clear 1.5 MOA - 3 small separate groups
- new brass has 2.255" neck which I bumped up too 2.262" neck distance (from fully free formed 2.270" max")
- new brass trimmed to 2.564
- impacts 1.2" left; 1.2" right and 1.3" down of dead center
3) NEW BRASS loaded 5/31/25 : 2930 fps - 8.7 STD (next 5 - 30 sec cooling per) easy MOA)
- impacts lower half of 1" circle

- To be fair, I now try to clean between every 100-200 rounds in the bolt. This may be a mistake for PRC loads? I'll clearly check to see next time I can try.
- I now have 2nd reused brass from the 1st time redo attempt. Now trying to follow the same exact process for neck resize with mandrel and inside case lube as with new brass. Maybe doing that before case cleaning with 1st fired brass caused tention issues but neck lude is always last.
- I may just have to accept that I need to resize all future brass the exact same way and re-do a seating depth / power charge to tune it back in. I should throw in that my barrel now has only about 150 rounds through it so unclear if/how breaking in changes any other parameters here?

 

[Rocketmandb]

Thanks for the feedback so far.. I'll be doing my first 1,000 yrd trials with the 300 PRC soon here in July so I'll see how that turns out. But to respond here per comments:
- Reference shoot all on same day in this order:
- 300 PRC load: New lapua brass no trim; BR primers; 81.2 grn H1000; Berger 215 Hybrid Target; seated at ~3.7" COAL (ojive 2.915")
(All reference 5 shots - 100 yrd range - indoor - no wind)
1) NEW BRASS loaded 3/15/25 : 2924 fps - 6.4 STD (first 5 - 30 sec cooling per) easy <MOA)
- all centered with scope
2) 1st Resized loaded 6/19/25 : 2916 fps - 9.8 STD (next 5 - 30 sec cooling per) clear 1.5 MOA - 3 small separate groups
- new brass has 2.255" neck which I bumped up too 2.262" neck distance (from fully free formed 2.270" max")
- new brass trimmed to 2.564
- impacts 1.2" left; 1.2" right and 1.3" down of dead center
3) NEW BRASS loaded 5/31/25 : 2930 fps - 8.7 STD (next 5 - 30 sec cooling per) easy MOA)
- impacts lower half of 1" circle

- To be fair, I now try to clean between every 100-200 rounds in the bolt. This may be a mistake for PRC loads? I'll clearly check to see next time I can try.
- I now have 2nd reused brass from the 1st time redo attempt. Now trying to follow the same exact process for neck resize with mandrel and inside case lube as with new brass. Maybe doing that before case cleaning with 1st fired brass caused tention issues but neck lude is always last.
- I may just have to accept that I need to resize all future brass the exact same way and re-do a seating depth / power charge to tune it back in. I should throw in that my barrel now has only about 150 rounds through it so unclear if/how breaking in changes any other parameters here?

Some notes:

- I'm not clear on how many rounds you fired. It looks like only 5 per. If so, that's not nearly enough to get any meaningful data.

- Your brass prep steps contain some important steps, namely annealing, mandrel and neck lube.

- Lapua brass has EXTREMELY tight necks out of the box. Using a mandrel opens them up somewhat, but because they are so tight, they spring back more. This yields a higher seating force, which corresponds to a higher force holding the bullet in the neck. Neck lube helps here, but virgin necks will still deliver substantially higher forces.

- Anything that impacts how the bullet starts moving (e.g. the force holding the bullet in the neck, powder temp, bullet weight, etc.) will change the pressure profile. When you change the pressure profile, you change how the bullet accelerates. This, in turn, can have a down range impact.

- So, your new brass potentially yielded decent results because the pressure profile was a good match for your chamber/barrel/bullet combo. As soon as you fired and annealed it, everything changed. There is less force holding the bullet in place, meaning the pressure curve is a little flatter, meaning the acceleration starts slightly sooner and is slightly lower.

- This is why I don't waste my time doing load dev with virgin brass. While the impacts of using virgin brass are small, they are there.

- You haven't played with seating depth at all. This can, and usually will, make a significant impact. In the image below, these are seating depth tests from a few years ago. The lower right (don't ask me why I started there - I don't know) was 5 shots from my 300 PRC with 230 Berger OTMs seated .015" off. The upper left is 3 at .018" off and the upper middle is 3 at .021" off. I stopped the test at that point, set my remaining rounds to .018" and validated.

What I do:

- Fire enough rounds using virgin Lapua to get 50 fired cases - minimum.

- Run a ladder to find an area that gives you decent SDs - you don't have to run the entire range dictated by a loading manual. I usually start in the regime where I want the velocity to be, drop down a bit, then go up at .3 grains per 5-shot group. This won't definitively tell you what's good, but you get a pretty good idea of what's bad. Pick a couple of the more promising "not bad" loads and load up like 20 of each to validate.

- If you're lucky, like I just was with my 300 PRC using a new powder (VV N568), while doing the ladder you happen to be at a seating depth that works. Otherwise...

- Do a seating depth test starting at like .015" off and move up at .003" increments. With Berger hybrids, you will usually find something that works before you hit .030". The highest I've ever gone before hitting a good setting is .039". Most tend to hit before .030"

- Validate the seating depth.

 

[Emerson0311]

Do you know if there is a velocity difference between the virgin brass loads and the reloads?

I had to add a grain of powder to get the same velocities as the virgin firing with my Lapua brass.

 

[SaltyDog89]

I had to add a grain of powder to get the same velocities as the virgin firing with my Lapua brass.

My trials here may not show much difference yet. For a 5 shot careful trial: New Lapua brass averaged 2924.1 fps with 6.4 SD followed by 5 shot careful trial of 2nd time use brass of 2915.7 fps with 9.8 SD with both groups waiting a few minutes between each round to limit barrel heat up, in a temp controlled indoor 100 range.

 

[SaltyDog89]

Some notes:

- I'm not clear on how many rounds you fired. It looks like only 5 per. If so, that's not nearly enough to get any meaningful data.

- Your brass prep steps contain some important steps, namely annealing, mandrel and neck lube.

- Lapua brass has EXTREMELY tight necks out of the box. Using a mandrel opens them up somewhat, but because they are so tight, they spring back more. This yields a higher seating force, which corresponds to a higher force holding the bullet in the neck. Neck lube helps here, but virgin necks will still deliver substantially higher forces.

- Anything that impacts how the bullet starts moving (e.g. the force holding the bullet in the neck, powder temp, bullet weight, etc.) will change the pressure profile. When you change the pressure profile, you change how the bullet accelerates. This, in turn, can have a down range impact.

- So, your new brass potentially yielded decent results because the pressure profile was a good match for your chamber/barrel/bullet combo. As soon as you fired and annealed it, everything changed. There is less force holding the bullet in place, meaning the pressure curve is a little flatter, meaning the acceleration starts slightly sooner and is slightly lower.

- This is why I don't waste my time doing load dev with virgin brass. While the impacts of using virgin brass are small, they are there.

- You haven't played with seating depth at all. This can, and usually will, make a significant impact. In the image below, these are seating depth tests from a few years ago. The lower right (don't ask me why I started there - I don't know) was 5 shots from my 300 PRC with 230 Berger OTMs seated .015" off. The upper left is 3 at .018" off and the upper middle is 3 at .021" off. I stopped the test at that point, set my remaining rounds to .018" and validated.

View attachment 8719355

What I do:

- Fire enough rounds using virgin Lapua to get 50 fired cases - minimum.

- Run a ladder to find an area that gives you decent SDs - you don't have to run the entire range dictated by a loading manual. I usually start in the regime where I want the velocity to be, drop down a bit, then go up at .3 grains per 5-shot group. This won't definitively tell you what's good, but you get a pretty good idea of what's bad. Pick a couple of the more promising "not bad" loads and load up like 20 of each to validate.

- If you're lucky, like I just was with my 300 PRC using a new powder (VV N568), while doing the ladder you happen to be at a seating depth that works. Otherwise...

- Do a seating depth test starting at like .015" off and move up at .003" increments. With Berger hybrids, you will usually find something that works before you hit .030". The highest I've ever gone before hitting a good setting is .039". Most tend to hit before .030"

- Validate the seating depth.

Alot of good insight in this response so thank you! It will take me time again for me to burn off the new brass and it looks like re-do a ladder/seating run again is in my future. On a second note, I just completed my very first 1,000 yard shoot with my 300 PRC and it seemed unexpectedly rather easy. Used an Arken EP-5 35x scope that was solid, ultra clear and likely still over kill for 1000 yards with perfect MOA elevation setup alignment using the Shooter App with my dialed in bullet info. No issue hitting a 12" plate at that distance with light wind but that rolled off a bit trying to get wind shift right when the wind did pick up (which I'm totally new too). This was a 45 new brass fire event that gave me a 2,929.3 fps with 14.3 SD and seemingly great accuracy which seems very reasonable but with plenty of room to improve on.

 

[Rocketmandb]

On a second note, I just completed my very first 1,000 yard shoot with my 300 PRC and it seemed unexpectedly rather easy.

Yeah, the 300 PRC really starts to play at a mile and up. At 1000, you're sort of insulting your rifle

My 300 PRC is my favorite rifle, by a fair margin.

Used an Arken EP-5 35x scope that was solid, ultra clear and likely still over kill for 1000 yards with perfect MOA elevation setup alignment using the Shooter App with my dialed in bullet info.

A couple things about the Arken. It's a decent optic for the price, and 1000 yards is well within its capabilities. Where you'll start running into issues is when you regularly take it out to longer ranges. My first scope on my original 300 PRC was a Vortex PST Gen II that I moved over from another rifle. I let it sit there for a little too long and got lazy about getting a better optic. Worked fine out to about 1300 - 1500 yards or so. Beyond that, I found myself getting significant eye strain. You will likely find the same with the Arken.

Additionally, and this is a matter of personal preference, I really don't like xmas tree reticles for ELR shooting. At longer ranges, spotting splash is hard enough, adding all the noise of a busy reticle makes it just that much harder. My ELR optics are as clean as they can be - ZCO with an MPCT 1 and a March Genesis with the FML - both simple reticles. And with ELR, I would now never use a holdover (I have before) - I always dial for elevation and then hold for wind more than not - it's a lot easier to keep things straight and concentrate on wind. Speaking of which...

No issue hitting a 12" plate at that distance with light wind but that rolled off a bit trying to get wind shift right when the wind did pick up (which I'm totally new too).

I've been shooting ELR for getting on 10 years. I'm still new to wind too

I've got a video I'm almost done with where I'm shooting my 300 PRC that you might find interesting. I don't want to release it publicly yet, but I'll send you a PM with the unpublished link. One caveat: give me unfettered feedback!

 

[SaltyDog89]

Yeah, the 300 PRC really starts to play at a mile and up. At 1000, you're sort of insulting your rifle

My 300 PRC is my favorite rifle, by a fair margin.




A couple things about the Arken. It's a decent optic for the price, and 1000 yards is well within its capabilities. Where you'll start running into issues is when you regularly take it out to longer ranges. My first scope on my original 300 PRC was a Vortex PST Gen II that I moved over from another rifle. I let it sit there for a little too long and got lazy about getting a better optic. Worked fine out to about 1300 - 1500 yards or so. Beyond that, I found myself getting significant eye strain. You will likely find the same with the Arken.

Additionally, and this is a matter of personal preference, I really don't like xmas tree reticles for ELR shooting. At longer ranges, spotting splash is hard enough, adding all the noise of a busy reticle makes it just that much harder. My ELR optics are as clean as they can be - ZCO with an MPCT 1 and a March Genesis with the FML - both simple reticles. And with ELR, I would now never use a holdover (I have before) - I always dial for elevation and then hold for wind more than not - it's a lot easier to keep things straight and concentrate on wind. Speaking of which...



I've been shooting ELR for getting on 10 years. I'm still new to wind too

I've got a video I'm almost done with where I'm shooting my 300 PRC that you might find interesting. I don't want to release it publicly yet, but I'll send you a PM with the unpublished link. One caveat: give me unfettered feedback!

Once again, thank you for the insight here! I see that I'm clearly just a newbie compared your experience level.. Just added myself as a subscriber to your channel. First video I saw here with your like I could select was '.. Anatomy of a shot - why the little things matter'. I'll likely try to find and play with that 'Gordons reloading tool' later to see if the tool maybe can tell me how close to the red line my pressure could be.. The general thought question with this overall anatomy topic is; as the powder first starts to ignites, how much of the power is actually still not burnt by the time the bullet end first exits the end of the brass case fully (or not) and how much more time down the barrel is powder still igniting and pushing. Side question on what it means to the power ignition when slightly over compressed above 100% other than the obvious risk of over pressuring too quickly in the curve? Oh, I'm older electrical engineer hoping to retire within the next 5 years with some more side hobbies, like this one, with ideally moving and finding some good land somewhere I could actually do this hobby much more often with. I am currently more interested in the accuracy development & overall energy impact ballistics than hunting now but we'll see if that changes more to hunting in the future.. On a side note, I also enjoy my 8.6 blackout reloading experimentation and how this one seems to be on the rather tough side for managing how partial case fill affects subsonic accuracies itself when you are forced to not be able to fill fully and stay <1100 fps.

 

[Rocketmandb]

I'll likely try to find and play with that 'Gordons reloading tool' later to see if the tool maybe can tell me how close to the red line my pressure could be..

I did a quick setup with Gordons with 81.2gr of H1000 - here is the output:

This is showing about 2900 fps, but at 70 degrees. I didn't see what your temps were when you were shooting, but I'd guess a little higher.

Playing around with temps shows you hitting pressure at about 89 degrees at 2917 fps. Every rifle is different, and this is just a reference, but I'd guess you're right at about pressure right now. Close enough that small changes in things like primers, temps, etc. could put you over the top, if you're not there already.

The general thought question with this overall anatomy topic is; as the powder first starts to ignites, how much of the power is actually still not burnt by the time the bullet end first exits the end of the brass case fully (or not) and how much more time down the barrel is powder still igniting and pushing.

Totally depends on the powder and barrel length. Gordons has a burn rate calculation to see if you're spitting powder out the end, but doesn't tell you (afaik) how much is burning in the barrel.

Side question on what it means to the power ignition when slightly over compressed above 100% other than the obvious risk of over pressuring too quickly in the curve?

A theoretical ideal load is one that gives you:
- Good SDs
- No powder shooting out the end of the barrel
- The velocity you're looking for
- Close to 100% case fill

Light compression is typically not an issue, though I prefer to avoid it. This issue with a decently compressed load that comes into play is when you start breaking kernels (or grinding them down). When that happens, you start to introduce variability in a couple ways:

- You can grind off some of the deterrent on the outside of affected kernels, which essentially raises the burn rate.
- You can create additional surface area, which also essentially raises the burn rate.
- The above can cause variability in burn rate because you are likely never crunching powder in two cases exactly the same.

My general thinking is that if you can hear the kernels crunching, they are shedding material. That's why I don't do it.

I use an extended drop tube for when I'm close to 100% fill as it helps the load settle a little better. You can also tap the case a few times on the bench to get it to settle a little better.

As an aside, for some reason I'm unable to send you a PM.

 

[SaltyDog89]

Once again, a lot of appreciated detail and a special thanks for the Gordon's chart details! Very good that at least some real data shows that I'm reasonably OK with the 81.2 grain of H1000 but need to watch for any issues if I do something stupid or if temps are on the high side. Oh, your videos seem very enlightening and very well made! You cover many details that I know but it's mixed with many misc smaller little extras that are very good to know and keep in mind. In all, they seem extremely useful to newer & intermediate level reloaders (where I fall in) for the larger calibers like the 300 PRC... For now, I'll be stuck to periodic visits to shorter ranges which will keep my focus on the quest for perfect load developments and these associated strategies.

 

[SaltyDog89]

I did a quick setup with Gordons with 81.2gr of H1000 - here is the output:

View attachment 8722709

This is showing about 2900 fps, but at 70 degrees. I didn't see what your temps were when you were shooting, but I'd guess a little higher.

Playing around with temps shows you hitting pressure at about 89 degrees at 2917 fps. Every rifle is different, and this is just a reference, but I'd guess you're right at about pressure right now. Close enough that small changes in things like primers, temps, etc. could put you over the top, if you're not there already.




Totally depends on the powder and barrel length. Gordons has a burn rate calculation to see if you're spitting powder out the end, but doesn't tell you (afaik) how much is burning in the barrel.



A theoretical ideal load is one that gives you:
- Good SDs
- No powder shooting out the end of the barrel
- The velocity you're looking for
- Close to 100% case fill

Light compression is typically not an issue, though I prefer to avoid it. This issue with a decently compressed load that comes into play is when you start breaking kernels (or grinding them down). When that happens, you start to introduce variability in a couple ways:

- You can grind off some of the deterrent on the outside of affected kernels, which essentially raises the burn rate.
- You can create additional surface area, which also essentially raises the burn rate.
- The above can cause variability in burn rate because you are likely never crunching powder in two cases exactly the same.

My general thinking is that if you can hear the kernels crunching, they are shedding material. That's why I don't do it.

I use an extended drop tube for when I'm close to 100% fill as it helps the load settle a little better. You can also tap the case a few times on the bench to get it to settle a little better.

As an aside, for some reason I'm unable to send you a PM.

I should have asked with your 300 PRC focus. Sorry, but if you covered this in one of your videos then I either missed it or didn't get to it yet. Question: what is your exact 300 PRC case trim length that you use vs what may be floating around for what is recommended you trim too before you deburr?

 

[Rocketmandb]

I should have asked with your 300 PRC focus. Sorry, but if you covered this in one of your videos then I either missed it or didn't get to it yet. Question: what is your exact 300 PRC case trim length that you use vs what may be floating around for what is recommended you trim too before you deburr?

First off, when it comes to trimming for the first go on brass, I'm lazy. I want to use my Henderson trimmer so I can trim and chamfer in/out in one go. To do so, I'll measure the shortest brass of the new stuff I'm setting up, then trim everything to that.

After I shoot for the first few times, and size the brass for the next go, I find the longest case, chamber it, and use a borescope to see how close it is to the end of the chamber. Usually it takes a couple/few firings to get decently close. Once the longest piece of brass gets close enough for my taste, I set the trim length to that (and never touch it again) and trim as necessary after sizing each time.

The reason I want the trim length to be close to chamber length is to minimize the area where carbon rings will form. Cleaning carbon rings is always a pain, so I want to do so as little as possible - though I've recently found a way to do so by setting up a system and letting it run for 24 hours. Even though it's easier, however, it doesn't change the fact that I don't want to do it.

 

[SaltyDog89]

Such an interesting response that adds to how you've really been at this for a while and how I'm still way new to many nuances of what it takes as one strives for the best constancy of reloading matched with the gun itself. I had no plans to go down a borescope path or even know that carbon ring build up was a thing to worry about in the chamber but clearly something I'll add to my list of things to be aware of in the future. You also just indirectly made me question everything I do in regards to 'proper' barrel cleaning now and how I've neglected to worry about that too much which is likely another large mistake I have to correct. Thank you for the response! Oh, and thanks for hurting my head more

 

[Rocketmandb]

You also just indirectly made me question everything I do in regards to 'proper' barrel cleaning now and how I've neglected to worry about that too much which is likely another large mistake I have to correct.

Honestly, I've found it difficult to clean with any reasonable regimen and keep carbon rings at bay. Typically, your bore guide will interfere with cleaning where carbon rings tend to form. That's why I try to delay them by minimizing the area in the throat where carbon tends to build up. Then, clean them out when they happen.

As to getting a bore scope. They're cheap and worth getting, but don't overuse them or overthink what you see. Pretty much the only reasons I have one are for what I mentioned above and for checking to see if one is forming