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300 PRC update

Wow that is stock pile lol I like smk my go to bullet. I run 183 smk and 197 smk in my 7mms. What is the bc you use on the 200 smk
I run a G1 of 694 with my Garmin 701, can't remember offhand what G7 I use, but I'm getting 3240fps out of the 300 Norma with 90gn's of RS76.
It is within a click out to a mile, which is the furthest I have shot out to.
I have hit a 1moa & 1/2 moa at a mile using them in my 300 Norma and 1moa in the 300 PRC.
 
That’s correct. I can get the 2850 with the 250s. Haven’t worked up a load yet because I’ve got a new barrel on the way and didn’t want to waste limited supplies. This was just a test to see what it would do with the factory tube.

The 3200 was from your post.
 
That’s correct. I can get the 2850 with the 250s. Haven’t worked up a load yet because I’ve got a new barrel on the way and didn’t want to waste limited supplies. This was just a test to see what it would do with the factory tube.

The 3200 was from your post.
Maybe I need to have a rethink on using the heavies, but to be honest, here in the UK the max range is a mile where I am.
The lighter recoil is nice and I'm hit the steel... Still it's nice to experiment.
I have some 215 berger hybrid, and 230 sierras I'lll try some of them.
Thanks for the info.
 
Maybe I need to have a rethink on using the heavies, but to be honest, here in the UK the max range is a mile where I am.
The lighter recoil is nice and I'm hit the steel... Still it's nice to experiment.
I have some 215 berger hybrid, and 230 sierras I'lll try some of them.
Thanks for the info.
At 1 mile not a huge difference but still noticeable wind. But that's if you get the 250 at 2850. Which is very doable specially in the norma. Those 230 Sierra should work great
 
The lighter recoil is nice and I'm hit the steel...

Run the numbers through JBM out to 2500. At 1500 you still get less wind drift with the heavies at 100-200 fps slower. That ends up being less recoil than the lighter bullet at faster speed or about the same. Drop is more with the heavies but wind drift is better.
 
Can I ask why you guys use heavy bullets in the PRC?
I have been using 200gn Sierra's the new #2231 pointed out to a mile on 1 MOA plates with good results.
Getting 3200fps with no pressure.
Just wondering?
Is it all about BC and wind?

1. I like to win
2. I've hit 1 MOA plates with most 30 cal bullets at 1 mile....but more than 50% hit rate....nope on all but 3 bullets I've used.
3. I've run 230's over 3000fps...but I've dialed back a bit.
4. BC really helps well past a mile. It extends my supersonic range and gives me more range for the useable elevation in my scope. My current load and scope setup can get me to about 2350 before I have to start holding over.

But....wind is everything in ELR...if you give up too much on the BC.....you fail. Sure, you have to have really tight SD's on your velocity and get that vertical spread down....but you can work that on most any bullet....some just take more work than others....but the ability to negate more wind with one bullet over another....just hard to do without.

5. I'm probably using less powder...and in today's world...that is huge.
 
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Hey guys, wanted to pick your brains on something I have never seen before. I thought I had a pretty solid load in my 300 prc but I’m getting a ES jumper in about every group.

Lapua brass, this is the second firing, annealed on a AMP, full length sized with Redding bushing die, mandrel to set neck tension.

Berger 215 hybrid, 78.4 of h-1000, federal 215m. Accuracy is certainly there, groups are hovering in the .4’s but in just about every 5 shot string over the Labradar there will be great ES except for one round. Yesterday’s numbers:
2997
2936
2934
2931
2931
I have a bunch of 5 shot groups that look exactly like this. A wild jump then single digit for the rest of the string. 90% of the time it’s the first shot that spikes.

I’m changing primers today to see what that does, tried N565 yesterday and the accuracy wasn’t as good as H-1000. All charges are on a FX-120i (v3) so I don’t think it’s my scale. Weighted the brass and don’t see anything out of the ordinary to account for a 60fps jump. Any thoughts on what else to try?
 
Working up loads for my new mile-build/attempt. Using N565 and 7828SSC for now with H225 gn ELDMs.
ladder loads and initial groups look promising. I'm able to get almost 3k with each powder without pressure. Have 230A-tips ready once I've got a few more rounds down it. SD was 10ish.

This is my first attempt at serious accurate brass prep/reloading. Neck turning, co-centricity testing, dry neck lube, 4 deg champher ect. I shouldn't have to keep them super fast as I can rainbow them in with the Ivey 200MA base.
 

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Working up loads for my new mile-build/attempt. Using N565 and 7828SSC for now with H225 gn ELDMs.
ladder loads and initial groups look promising. I'm able to get almost 3k with each powder without pressure. Have 230A-tips ready once I've got a few more rounds down it. SD was 10ish.

This is my first attempt at serious accurate brass prep/reloading. Neck turning, co-centricity testing, dry neck lube, 4 deg champher ect. I shouldn't have to keep them super fast as I can rainbow them in with the Ivey 200MA base.

You don't need an IVEY to get to 1 mile....with the 300PRC it is just a short poke. You will probably be about 16mils on your dial. The mile shot is both a tough personal mile stone...and not hard at the same time. With knowledge and experience you will find it fairly easy to make a hit within a few shots on a fair size target...but at first it may frustrate the hell out of you.

With the 225 ELD-M's.....a load of 78.5gr of N565 is probably where you are going to find a happy place in all conditions... Winter-Summer...and sea level to the Alps.....in the Arizona dry...to the South Georgia humidity.

For seating depth....do my preferred method. Take the brass in your left hand...take the 225-ELD in your right hand....hold both arms up with the brass and bullet at eye level. Now...bring your arms together to where the bullet and brass are touching parallel to each other. Now....look at the brass...do you see where the neck and the shoulder meet?....good.....Now look at the bullet...do you see where the bearing surface and the boat tail meet?....good. Now...seat that bullet to where that boat tail/bearing surface....meets that neck/shoulder junction. Shoot some three shot groups...or even two shot groups....if they aren't touching...extend that Cartridge Over All Length out by 3 thou..and continue until you find where you are shooting one holers.....extend outwards until the group goes to shit....now take the longest COAL that shoots bugholes....and as your throat erodes...and your bullet jumps...it will be good until you hit the first measurement where you saw bugholes...in relation to bullet jump.

Generally....by the time you run out of this seating depth node...it is time to replace the barrel with 1200-1500 rounds....or more with the 400MODBB steel.

2 thou shoulder bump is your friend.....consistency of your reloading process is your friend.

Good luck...and remember.....Always...ALWAYS have fun.
 
great input, thanks. I've already been thinking about/checking the COAL in relation to the method you mentioned. For now I am sticking with mag len, but I do specifically remember checking to make sure they matched shoulder and boat tail fairly closely as you mentioned. I bought the Ivey for the 6.5 originally. I have preprocessed some brass, but going to hold off on loading more for now.
 
Hi All

I'm building out a dedicated 2000 yard bench rifle in 300 PRC. Weight is not an issue so I'm going with the MPA Matrix chassis, with MPA's in house barrel (MTU Profile) 1:9 twist, and Curtis Custom Action (either Helix or Valor).

The question is barrel length (28" or 30"), and I've searched this forum and read dozens of posts and I see several folks going with 28"-30" barrels to maximize velocity. I also called Hornady and spoke to them about the whether their factory 225gr ELD Match ammo is still burning powder past 28" and they said "Yes, you can squeeze out an additional 30-40 fps going from 28" to 30".

An additional 30-40 fps out of factory ammo doesn't seem like a big deal but I'm guessing if I eventually switch over to hand loads I should be able to squeeze out a bit more speed with the 30" barrel?

So before making this decision I'd like feedback from folks on the board: Are there any performance downsides for the 300 PRC cartridge out of a 30" barrel for my build?

thanks in advance for everyone's feedback
 
There are two downsides to a longer barrel, and one of them is theoretical.
  • A longer barrel technically has lower frequency vibration modes, so the induced oscillations will be slightly higher amplitude. In theory this has an impact on group size. 28 vs 30, probably not.
  • The rifle will be more unwieldy.
Velocity is nice for something you won’t be carrying too much though.
 
I run a 29.5".....not 30...because 29.5" was what it ended up being after trimming some not perfect off the ends.

A 300PRC makes a nice 1000-2000 yard rifle....I've loved mine so far. However....once past 1500yds.....before a mile....the 225 ELD-M's are going to perform the way you want them to.....especially 'Match' retail loads. You really want to get into hand loading and get you some precision rounds on those targets....the muzzle velocity extreme spread is going to eat your lunch at 2k....and the BC of the ELD-M...while good...is NOT consistent from bullet to bullet. Go with some A-Tips...or some Bergers.

Anyway....I hope you enjoy your 300PRC as much as I have mine.
 
There are two downsides to a longer barrel, and one of them is theoretical.
  • A longer barrel technically has lower frequency vibration modes, so the induced oscillations will be slightly higher amplitude. In theory this has an impact on group size. 28 vs 30, probably not.
  • The rifle will be more unwieldy.
Velocity is nice for something you won’t be carrying too much though.
Thanks, this will be a bench rifle so I'm not too worried about it being unwieldy, but you make an interesting point regarding oscillation amplitude. Hopefully the thicker MTU profile will minimize this potential issue.

looong barrel w low mount + big brake/supressor + lots of elevation ~ blurry scope? but 30" does sound nice.
Definitely a consideration, but do you think that's going to be noticeably different between 28" & 30"?

I run a 29.5".....not 30...because 29.5" was what it ended up being after trimming some not perfect off the ends.

A 300PRC makes a nice 1000-2000 yard rifle....I've loved mine so far. However....once past 1500yds.....before a mile....the 225 ELD-M's are going to perform the way you want them to.....especially 'Match' retail loads. You really want to get into hand loading and get you some precision rounds on those targets....the muzzle velocity extreme spread is going to eat your lunch at 2k....and the BC of the ELD-M...while good...is NOT consistent from bullet to bullet. Go with some A-Tips...or some Bergers.

Anyway....I hope you enjoy your 300PRC as much as I have mine.
Thanks for the feedback. I assume in the above in bold you meant "aren't going to perform"?

Good feedback on the A-Tips and Bergers for custom loads, will definitely prioritize these options. Problem right now is the lead times for custom builds is 5-6 months so at least I'll have time to find factory ammo as well as custom hand loads LOL!

I have 28” and 30” magnum barrels.
No complaints.
My next 338 barrel is going to be 32”

Excellent! thanks for the feedback, 30" barrel it is 💪
 
I’ll try to add to this thread before starting a new one. I ordered up a 300prc conversion kit for my Desert Tech SRS A1 this summer for an elk hunt. I ended up developing a load for the 220gr ELDXs using Hornady brass (all I could find at the time) 77.6gr of H1000, and CCI250s. That load had single digit SD with an average velocity of 2,850 from a 26” barrel. I kinda wanted 2900 but they were more inconsistent.

Anyways, I shot 76 rounds during load development and dope verification out to 850 yards before my hunt. Every round I loaded was from brand new Hornady brass that I did a quick pass through a full length sizing die to straighten out the necks. When I got back from my hunt, I decided to size and load all of my once fired brass so everything can be put away for awhile. Upon inspection, I’ve got 15 cases that either have a crack or look close to starting a crack at the classic sign of case head separation. A couple of them have a faint ejector mark from when I was pushing for velocity a little, but most do not. I’ve pushed brass harder than this in several other guns and calibers and have never had a concern about case head separation after the fist firing.
Obviously I have either a headspace issue or a bad batch of brass, or a combination of both. I need to track down a headspace gauge and I’ll shoot a round this weekend to compare my fired brass to a new resized one.
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I’ll try to add to this thread before starting a new one. I ordered up a 300prc conversion kit for my Desert Tech SRS A1 this summer for an elk hunt. I ended up developing a load for the 220gr ELDXs using Hornady brass (all I could find at the time) 77.6gr of H1000, and CCI250s. That load had single digit SD with an average velocity of 2,850 from a 26” barrel. I kinda wanted 2900 but they were more inconsistent.

Anyways, I shot 76 rounds during load development and dope verification out to 850 yards before my hunt. Every round I loaded was from brand new Hornady brass that I did a quick pass through a full length sizing die to straighten out the necks. When I got back from my hunt, I decided to size and load all of my once fired brass so everything can be put away for awhile. Upon inspection, I’ve got 15 cases that either have a crack or look close to starting a crack at the classic sign of case head separation. A couple of them have a faint ejector mark from when I was pushing for velocity a little, but most do not. I’ve pushed brass harder than this in several other guns and calibers and have never had a concern about case head separation after the fist firing.
Obviously I have either a headspace issue or a bad batch of brass, or a combination of both. I need to track down a headspace gauge and I’ll shoot a round this weekend to compare my fired brass to a new resized one. View attachment 7730184View attachment 7730185View attachment 7730186View attachment 7730187
I think you nailed it headspsce, brass or over pressure. I've had some bad Hornady brass in past but can't speak on 300 prc Hornady brass.
 
wow, good catch. I've had that from 6.5 Horn brass when I was sizing it way too much (learning). Even then it took 4 or 5 loadings. I now bump minimally...Not saying that's the case here.
That Chassis looks awesome. I just scored ~75 new ADG cases
I'm about to load some more mild-moderate loads and try this weekend after the local match.
I just ordered an AMP Annealer, I guess my question now is should I anneal size and neck trim the virgin cases, or shoot them all once then do all that?
My max yardage right now is 1250 so I can load them nice and soft for initial fire forming and look for higher vel nodes on the next round.
 
I’ll try to add to this thread before starting a new one. I ordered up a 300prc conversion kit for my Desert Tech SRS A1 this summer for an elk hunt. I ended up developing a load for the 220gr ELDXs using Hornady brass (all I could find at the time) 77.6gr of H1000, and CCI250s. That load had single digit SD with an average velocity of 2,850 from a 26” barrel. I kinda wanted 2900 but they were more inconsistent.

Anyways, I shot 76 rounds during load development and dope verification out to 850 yards before my hunt. Every round I loaded was from brand new Hornady brass that I did a quick pass through a full length sizing die to straighten out the necks. When I got back from my hunt, I decided to size and load all of my once fired brass so everything can be put away for awhile. Upon inspection, I’ve got 15 cases that either have a crack or look close to starting a crack at the classic sign of case head separation. A couple of them have a faint ejector mark from when I was pushing for velocity a little, but most do not. I’ve pushed brass harder than this in several other guns and calibers and have never had a concern about case head separation after the fist firing.
Obviously I have either a headspace issue or a bad batch of brass, or a combination of both. I need to track down a headspace gauge and I’ll shoot a round this weekend to compare my fired brass to a new resized one. View attachment 7730184View attachment 7730185View attachment 7730186View attachment 7730187

Well, the big picture is a bummer, but at least you didn't have a horrible failure that led to injury. It is significant to this issue that DT's have strong actions and can take pretty high pressure. I'm not a fan of Hornady brass for reloading, but I have reloaded it for a few calibers without problems. I'd be tempted to push a few primers into your failed brass and some of the once-fired brass. If you have any virgin brass, that would be good for comparison. You might get a hint about whether your reloads were a big part of the picture or if headspace was the major factor. When I'm working up a load, I measure base-to-datum unfired and fired, after sizing, then after second firing, just to find out what's happening in the chamber. I want to get to where I size the case body and neck as little as possible and still function properly.

Do what you have to do to get some Lapua or ADG brass. Good luck trouble shooting it.
 
Right now I have to lean headspace because my loads fall in line powder charge and velocity wise with the many posts of real world data in this thread. I’ve never experienced case head separation in almost 25 years of reloading. Granted, I haven’t pushed a cartridge to the edge for several firings like some do, but to have new brass do this is something new for me. My bullets were .020 off the lands and most of the bad brass doesn’t even have an ejector mark or any other obvious sign of pressure. Also, all rounds were clocked with my labradar and all charge weights made sense.
 
wow...that is some serious head space issues. I've pushed Hornady, ADG, and Lapua brass harder than anyone that I know of...and the only time I had case head separation starting was on some brass that I over sized 9 thou or more. If you follow the direction on most reloading dies....you'll be over sizing...sometimes....a lot....but it will fit.

I've been annealing then mandreling the necks on virgin Lapua brass and just running them in comps.....works really well.
 
Yes, I normally have my sizing die just kiss the shell holder on the cam-over. Does anyone have a good measurement on new unsized Hornady brass using the Hornady headspace comparator tool? Everything I have has been sized except a modified case for my OAL tool but I’m not sure how accurate that would be.
 
Yes, I normally have my sizing die just kiss the shell holder on the cam-over. Does anyone have a good measurement on new unsized Hornady brass using the Hornady headspace comparator tool? Everything I have has been sized except a modified case for my OAL tool but I’m not sure how accurate that would be.

That's not going to be a good idea....it's a 'comparator'...to itself.....each one manufactured is probably going to give a slightly different to hugely different measurement. I for one will only use a SAC comparator......with the neck/shoulder angle specific insert...and even still...it is a comparator to itself.

Take one of your fired cases...measure it....and try to set your die to bump it back 2 thou from there.
 
Yeah, I get that. I wished I had one unmolested new piece so I could immediately figure out if I originally oversized the new brass or there is an issue with my barrel/and or brass. I can’t imagine how I could wrongly size brand new brass to this point of case failure from a single firing. I load probably 20 different calibers and have always setup my sizing die the same way.
 
Yeah, I get that. I wished I had one unmolested new piece so I could immediately figure out if I originally oversized the new brass or there is an issue with my barrel/and or brass. I can’t imagine how I could wrongly size brand new brass to this point of case failure from a single firing. I load probably 20 different calibers and have always setup my sizing die the same way.
I always note new brass, go gauge(and how much packing tape to get to stop point) and fired brass base to ogive length for each barrel.
 
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Well I’ve always used my once fired cases for documentation and just assumed new brass would be slightly undersized so I never paid a whole lot of attention to it other than straightening out the necks and chamfering the mouths. I’ll change that for sure. The only new data I have without shooting it again is comparing the Hornady modified case to one of my sized new cases of loaded rounds. I’m showing a shoulder bump of 7-8 thousandths. I have no idea if those modified cases are standard issue new brass with a threaded hole and no neck tension. I’ll have more fired data this weekend.
 
Fun fact....virgin Lapua brass is EXACTLY 2 thou bump back from my fired brass....crazy. So...I anneal and mandrel, chamfer...and load...as long as I get a 20in/lb-ish seating force that is consistent from brass to brass....it's going to be a good day.
 
Stealthy ... regarding the 20in/lb seating force ... how would that compare to typcial neck tension goals? 2K?

I can get 20 lbs (it's not inch-pounds, just straight up pounds) on my 6 BRA very consistently. I get 40ish on my 300 PRC, and not nearly as consistent. And you can't compare seating force to typical "neck tension" goals because there are a significant amount of variables involved. Neck tension measured in thousandths of inches is a ridiculously absurd definition and measurement. Neck tension is more appropriately defined as the force holding the bullet in, which is definitively the force of friction holding it in. Friction is defined as the force acting against the bearing surface multiplied by the area multiplied by the coefficient of friction (how "sticky" something is).

Why is this not an exact science? Remember - force, area, coefficient of friction:

- Out of those three things, the only one that is likely to remain consistent is the area (inner circumference x neck height) of the neck that's touching the bullet - unfortunately, even there you may have inconsistent necks that cause variation in force along the length (more below).

- The force acting against the bullet by the neck is caused by the brass springing back after it's been opened up while inserting the bullet. This can be influenced by softness of the brass (which is why consistent annealing plays a part), neck thickness (which is why consistent neck thickness plays a part), and how much the brass moves (which is why using a mandrel and picking the right bushing play a part).

- The coefficient of friction is influenced by using lube, carbon left in the neck, etc. Also, as mentioned above, if you have a neck that's inconsistent along its length, you don't get uniform force along its length acting with the coefficient of friction.

In short, be consistent with all of the above mentioned items (sizing, annealing, lube, etc.) and you will get consistent neck tension. Why can you not match it up to the typical ".002 inch" neck tension? Because the actual force holding the bullet in from that .002" varies DRAMATICALLY based on the material make up of the brass, how it was prepped, how it was sized, etc.

Notes:

- I have some interesting data on this thread - it's for my 6 BRA, but an interesting read none the less.
- On my 300 PRC, I get 40 lbs when using graphite lube and one bushing - when I go up .001" in bushing size, it opens it up too much
- Without lube and mandrel, I'd get up over 70 on some rounds
- I have a fair amount of inconsistency (all relative!) on neck thickness with my 300 PRC ADG brass vs. what I see on my 6 BRA Lapua brass. Sort of apples and oranges, but I don't yet have 300 PRC Lapua brass to compare it to.

TLDR:

Measuring neck tension by size of neck is an absurd measurement. Using seating force is much better, but is not perfect either - but it's the best thing we've got. Measure seating force, go for consistency, then once there, play with it by using different bushing and mandrel sizes - if you really need to. Chances are you won't - consistency matters most.

As an aside, the most accurate way to measure "neck tension" is to pull bullets and measure the pulling force. Of course that sort of defeats the point :)
 
At the Precision Rifle Expo we ran 230
A-Tips @ 2850 in a 300 prc. 80 grains of N570

Most everyone shooting was able to do about .7moa or better at 1k on the shot marker.
 
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I do. Please keep us posted, I’d love a Win Mag without having to fuck around with the belt. Is there a pic or a print somewhere of this cartridge?
I’m not aware of or lack experience with “fucking around with the belt. I’ve reloaded for 300 win mag and 30-338 mag(same case) quite a bit but I’m not aware of any unusual difficulties. Is it because it headspaces from the belt? Thanks