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300 PRC update

We ordered a 30" Bartlein barrel for the AX MC in March from Mile High and it arrived right before our planned 3 day weekend shooting trip. I picked up a Sidewinder brake and couple of boxes of ELDM 225s. The weekend was a blast and all the sudden it was Sunday and we had not shot the 300 PRC. So I screwed it in and it shot like a dream. The stats were not all that impressive but I have to remind myself we were breaking in a new barrel. Average = 2941, SD = 18.2 FPS, ES = 94. The last 10 were Avg = 2956, SD = 15.6, ES = 56 but they included the high MV outlier. The last 5 were Avg =2952, SD = 7.0, ES= 16.

I don't know if it was due to the mass of the AX plus the heavy barrel and a great brake or whatever, but the recoil was mild. It was easy to spot shots. We love it. Eventually, I'll handload for it but for now, we'll just stretch it out on factory ammo.
 
Thinking of using the 300PRC as a suppressed hunting rig. Seems that it really needs a long barrel to take advantage of a full powder burn, has anyone tried a 22” barrel suppressed? Those that are really familiar with this caliber, what your best guess? 2800 FPS?
 
We ordered a 30" Bartlein barrel for the AX MC in March from Mile High and it arrived right before our planned 3 day weekend shooting trip. I picked up a Sidewinder brake and couple of boxes of ELDM 225s. The weekend was a blast and all the sudden it was Sunday and we had not shot the 300 PRC. So I screwed it in and it shot like a dream. The stats were not all that impressive but I have to remind myself we were breaking in a new barrel. Average = 2941, SD = 18.2 FPS, ES = 94. The last 10 were Avg = 2956, SD = 15.6, ES = 56 but they included the high MV outlier. The last 5 were Avg =2952, SD = 7.0, ES= 16.

I don't know if it was due to the mass of the AX plus the heavy barrel and a great brake or whatever, but the recoil was mild. It was easy to spot shots. We love it. Eventually, I'll handload for it but for now, we'll just stretch it out on factory ammo.

Thanks for the info. I saw some pretty inconsistent results with the latest batch of 225 eldm I shot. My original lot I was in the high single digits SDs and average half inch 5 round groups. Some more. Some less.

I was really thinking of a 29-30 inch barrel handloading the 230s hoping to get 3k+ fps. If I couldn't get it there, then it may not be worth it for me. Haven't seen it yet from anyone. I may be just sticking with the 26" and 215s.
 
I'm getting 2965 fps from my 26" AXMC. I was shocked at the lack of recoil compared to my 300 Win Mag on the same rifle. I just wished I had saved the money and not bothered with the 338l setup. Consistent Hits at 1500 yds with 10mph full value wind. Rifle is a JOY!
 
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Because we can’t get it to 4000fps

However.....
You might want to keep tuned for the new high pressure proprietary cartridges that will be available shortly:

You might just get close to your 4000 fps with the right monolithics...
 
Ordered a 31 in bartlein blank in MTU contour 1 in 9 twist 5G. Just need to decide on the final finished length. Any recommendations?
 
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However.....
You might want to keep tuned for the new high pressure proprietary cartridges that will be available shortly:

You might just get close to your 4000 fps with the right monolithics...

Have been loosely following various ultra-high pressure concepts and while I'm sure there are materials out there that can handle it, I suspect barrel life is going to suffer considerably-- and it won't be cheap at all. 4140 and 416SS are already near their limit at 65,000psi on the inner (bore) wall.

Keeping an open mind, though. Curious to see what comes of it. Not convinced it will be here for the long term, yet.
 
Have been loosely following various ultra-high pressure concepts and while I'm sure there are materials out there that can handle it, I suspect barrel life is going to suffer considerably-- and it won't be cheap at all. 4140 and 416SS are already near their limit at 65,000psi on the inner (bore) wall.

Keeping an open mind, though. Curious to see what comes of it. Not convinced it will be here for the long term, yet.

Hi,

You are correct, there have been all sorts of concepts, etc for years and years :)
But the NGSW and its' high pressure 6.8 cartridge is changing the norm of pressures.

What most of them did not do though is to approach the situation in its' entirety but instead focusing on 1 aspect of it.

Changing barrel alloys alone is a band-aide approach.

But being able to change projectile composition and engraving friction while being able to use a faster burning powder but less of it, yet achieve higher MV changes the entire results and approach....instead of going bigger and bigger case designs with more and more slow powder.

It also has a LOT to do with the cartridge designs themselves...that is how/why BR guys can push their 6BR, etc to 65k pressures but yet sit there and reload 5 pieces of brass all damn day without much hassle at all. The design itself lends to liking those pressures.

Sincerely,
Theis
 
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I want 3000 fps out of a 29-30 inch tube or doesn't really give me anything over 300 win mags. If I can get the velocity without a bunch of pressure why not?? I was shooting 2000+ yards. So I'll take the higher BC pills and velocity. 3k doesn't seem like it would be that hard with the PRC and a 29-30 inch tube. If you can get low to mid 2900s with a 26 inch tube and factory 225s... the 3k hand loads and longer barrel seems well within reach. So I don't think it's asking a whole lot for less then 100 fps with hand loads and 4 more inches of barrel? Maybe it is.. guess I'll just find out for myself.
 
I want 3000 fps out of a 29-30 inch tube or doesn't really give me anything over 300 win mags. If I can get the velocity without a bunch of pressure why not?? I was shooting 2000+ yards. So I'll take the higher BC pills and velocity. 3k doesn't seem like it would be that hard with the PRC and a 29-30 inch tube. If you can get low to mid 2900s with a 26 inch tube and factory 225s... the 3k hand loads and longer barrel seems well within reach. So I don't think it's asking a whole lot for less then 100 fps with hand loads and 4 more inches of barrel? Maybe it is.. guess I'll just find out for myself.
sherman improve it
 
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Thanks for the info. I saw some pretty inconsistent results with the latest batch of 225 eldm I shot. My original lot I was in the high single digits SDs and average half inch 5 round groups. Some more. Some less.

I was really thinking of a 29-30 inch barrel handloading the 230s hoping to get 3k+ fps. If I couldn't get it there, then it may not be worth it for me. Haven't seen it yet from anyone. I may be just sticking with the 26" and 215s.
There's a reason for 300 NM. Just saying.
 
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I want 3000 fps out of a 29-30 inch tube or doesn't really give me anything over 300 win mags. If I can get the velocity without a bunch of pressure why not?? I was shooting 2000+ yards. So I'll take the higher BC pills and velocity. 3k doesn't seem like it would be that hard with the PRC and a 29-30 inch tube. If you can get low to mid 2900s with a 26 inch tube and factory 225s... the 3k hand loads and longer barrel seems well within reach. So I don't think it's asking a whole lot for less then 100 fps with hand loads and 4 more inches of barrel? Maybe it is.. guess I'll just find out for myself.

Maybe try the Warner flatline 198gr bullets in your 30" barrel (assuming at least a 9 twist) and see if you hit the velocities you were interested in?
 
Last weekend I finally got around to chambering a 300 PRC barrel for my DTA. I used a PTG saami reamer and a 10 twist K&P barrel(6-groove cut barrel). It finished at 27”.

Off to a good start. Here’s the first four rounds through the barrel with Hornady match 225 ammo. A bore sighted shot, and 3 round group. One round was slow and killed the ES/SD. Velocity average was 2873.

AFF9F338-B181-428F-B89D-7791433EA868.jpeg


I shot 5 more rounds of the same ammo at dots (top row, pic below), and the average jumped to 2907 FPS. As with the first four rounds, one slow round in this group killed the ES.

Below that are two ladders with 230 and 215 hybrids in half grain increments of H1000. All virgin brass and bullets jumped .030. Charge weight and velocity is written under each dot. Not sure what happened to the last round of the 230 at 76 grains, but it was oddly slow. Shot 19 was a ND. I interrupted my trigger squeeze to do a breath cycle, and capped a round off. Doh!

Edit: Just realized that I didn’t write the 215 charges or velocities on the target. It was 75-77.5 grains, and topped out at 2947FPS.
881F3923-B1FB-4200-AE77-F476BE0CDB79.jpeg


I’m still a grain or two from max for both bullets with H1000. Primer pockets are like new. Case head expansion numbers for both bullets maxed at .0003-.0004, which indicates the pressures were pretty soft. Now that I’ve got a little Experience with the PRC, i’ll go out and do a 500 yd OCW. I also have some other bullets to test, as well as RL26.

The DTA is a very new platform for me. I’ve only shot about 100 rounds through it with the factory 47 Lapua barrel, which shoots great. Easy gun to shoot well in general, which should help the 300 testing go well.

5A72553C-9854-4055-858D-A02408142BD1.jpeg
 
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Another range report, this time with fire formed 8x68S:

The last time I went to the range to test out 8x68S brass that had been fire formed, it was a bit of a bust because, even though I lowered the powder load to accommodate for the thicker brass, it fired a lot hotter than I thought it would. I'm going to the private range on Saturday to run a ladder test, but I went to the local 100 yard range this evening to break in the barrel on my brand new 6mm BRA - so I figured I'd play around with 4 loads of RL 26 in 8x68S with my 300 while I was there.

I ran 4 groups at 72, 72.5, 73 and 73.5 grains of RL 26 with 225 pills.

The 72 grain group was poor, with a relatively large ES/SD and poor group. It averaged 2843 fps.

The 72.5 and 73 grain groups were both excellent. The ES on the 72.5 gr group was 7 and the SD 4.2. On the 73 it was 10/8.0. Both groups were essentially each one big hole. The 72.5 average was 2870 fps and the 73 was 2879 fps, which is closer than they should be on a linear comparison, leading me to believe that the sweet spot lies in this range. The ladder test will hopefully confirm.

Not coincidentally, this is the same fps range where my 76.2 gr of H1000 is performing best in Hornady brass.

Long story short: the 8x68S brass is performing well, and I haven't even dialed it in yet.
 
Can someone help this newbie idiot? AI AICS chassis and magazine, Bighorn TL3 magnum bolt and bolt face. The bolt is sliding over the round and not chambering. I'm assuming it has something to do with the feed lips but I haven't been in the game long enough to know.

300 PRC in an AICS 300 Win Mag magazine
 

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Can someone help this newbie idiot? AI AICS chassis and magazine, Bighorn TL3 magnum bolt and bolt face. The bolt is sliding over the round and not chambering. I'm assuming it has something to do with the feed lips but I haven't been in the game long enough to know.

300 PRC in an AICS 300 Win Mag magazine
send picture with mag inserted. from the rear. bolt removed. that shows primer height
 
Thinking of using the 300PRC as a suppressed hunting rig. Seems that it really needs a long barrel to take advantage of a full powder burn, has anyone tried a 22” barrel suppressed? Those that are really familiar with this caliber, what your best guess? 2800 FPS?
I'll be getting running a 26" barrel suppressed later this month or next and will get back to you.
 
Thought I’d try some PRC KoolAid and see how I like it; so I ordered a new magnum RPR. The brass prep for my MK13 is laborious to say the least, but I wasn’t gonna rebarrel a good shooting 300WM just yet. Hoping to significantly cut down reloading time with this new rifle. I’d love to shave some weight off that 15lb Ruger. Proof is making the barrels, but I can’t find anyone making aftermarket handguards. Was hoping someone could weigh in that has tracked down a company making them. I’m not above installing the 24” Proof and cutting down the factory handguard but will save that option till last ?
How's the RPR in .300PRC? I'm going to buy one once I sell my .308 and get some money saved up.
 
For the money, it’s a great gun. I was zero’d and shooting 1 MOA five-shot groups at 1250yd with factory 225 ELD-M ammo in no time flat. Got MV (2840 average with 32 ES) while zeroing via LabRadar, and plugged bullet data into my Sig kilo ABS. I walked all the way out from 100, 500, 600, 750, 1000, then 1250 with the first box of ammo!!

Now the bad: factory muzzle brake weighs 15oz and looks hideous. Replaced with Surefire brake to allow use of 762RC. Handguard bushing has small tabs on the end toward the shooter that contact the scope rail. This would be fine if they were perfectly lined up; mine weren’t. The tabs had the scope rail in a bind and out of level. I removed the handguard and loosened the nut so the bushing could rotate. I lined everything back up and retorqued so everything is happy and straight. I will likely remove the tabs when I replace the factory barrel with a Proof 24” because this girl is hefty. Those are my only issues thus far. Only been to the range a couple times. Plan on getting to the 1700yd spot after the crops are out.

Hope this helps! Happy Thirsty Thursday!
 
@twh30
AICS and AX chassis magazines for the 300WM have different part numbers.
You need the AX specific ones... ask me how I know ;(

@Piper907 actually if that fixes the problem I'll be kind of pleased. This is just the magazine that came with the chassis. Will the AX 300WM seat properly in the AICS chassis without any modifications? And it fixes my problem?
 
^^ Those are what I'm using and haven't had a problem so far. Mags/stock interactions can be finicky.
 
Hey guy so I had Patriot Valley Arms build me a 300PRC and I have the flat line bullets does anyone has load data on what powders work best for the I currently have N560 and had some pretty descent groups but was wondering if anyone had luck with any other powders oh and by the way it’s a 26inch barrel and I’m getting 2950fps with hornady match 225gr eld m
 
Hey guy so I had Patriot Valley Arms build me a 300PRC and I have the flat line bullets does anyone has load data on what powders work best for the I currently have N560 and had some pretty descent groups but was wondering if anyone had luck with any other powders oh and by the way it’s a 26inch barrel and I’m getting 2950fps with hornady match 225gr eld m

Nice! What's the details on your 225 load?
 
Hey guy so I had Patriot Valley Arms build me a 300PRC and I have the flat line bullets does anyone has load data on what powders work best for the I currently have N560 and had some pretty descent groups but was wondering if anyone had luck with any other powders oh and by the way it’s a 26inch barrel and I’m getting 2950fps with hornady match 225gr eld m

Here’s the Flatline data (26in barrel, they also have a data sheet for 30in): https://www.warner-tool.com/wp-content/uploads/2019/04/300PRC_198Flatline_26inbbl.pdf
 
From what I can see/decipher I see no primer at all.

I would try opening the feed lips some. But I'd also consider what tooley mentioned

Yep. Just ordered a new mag with a longer COAL that I think is going to work. I also only live about 15 minutes from @DAVETOOLEY so I'll probably drop the whole build off with him to make sure I'm good to go. He might be able to open the feed lips on that old mag to make it work.

Thanks for the input.
 
Yep. Just ordered a new mag with a longer COAL that I think is going to work. I also only live about 15 minutes from @DAVETOOLEY so I'll probably drop the whole build off with him to make sure I'm good to go. He might be able to open the feed lips on that old mag to make it work.

Thanks for the input.
Oh hell somebody has found me.
Come on by.
 
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Went out again today to do 208 and 225 eld pressure test with H1000. For the 208’s no sight adjustment was made from the last outing, but the barrel had been removed and fully cleaned. I dialed .3 up for the 225 test. Interesting how the 208 trends down through the charge escalation. .8” total vertical through the whole range. The 225’s had almost exactly .36” of vertical through the whole range.


C4EC40A4-139F-42F6-805D-F026EDE02F0E.jpeg


The my DTA bolt makes these little halo ejector marks even at the lowest charges. Here’s the high end of today’s loads. 208’s on top. No sticky bolt for any of these.
06EB5732-69AF-472E-96C8-F5A0A460185E.jpeg



Other than finding zero, I normally wouldn’t do any of this at 100 yds. 500 and beyond is more useful. With my day job schedule though, I’m a little squeezed for time to set the long range tests up.
 
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Hope this helps! Happy Thirsty Thursday!
It sure does! I always shoot suppressed so I'm not worried about the muzzle device and the weight doesn't bother me either since I'll only be shooting it from a bench (or prone) and not lugging it around in the woods or anything. That's a little bit concerning about the tabs but it is a mass produced factory gun so these things happen-- at least it sounds like it was an easy fix. Thanks so much for the info, you've done basically exactly what I hope to. I'll be shooting factory ammo and really will only be using it beyond 1200yds which is why I don't want to dump a bunch of money into something custom. I only have access to that kind of range once a month at most but I can't get the .308 past 1400yds so it's time to start working on an upgrade!
 
Went out again today to do 208 and 225 eld pressure test with H1000. For the 208’s no sight adjustment was made from the last outing, but the barrel had been removed and fully cleaned. I dialed .3 up for the 225 test. Interesting how the 208 trends down through the charge escalation. .8” total vertical through the whole range. The 225’s had almost exactly .36” of vertical through the whole range.


View attachment 7126848

The my DTA bolt makes these little halo ejector marks even at the lowest charges. Here’s the high end of today’s loads. 208’s on top. No sticky bolt for any of these.
View attachment 7126849


Other than finding zero, I normally wouldn’t do any of this at 100 yds. 500 and beyond is more useful. With my day job schedule though, I’m a little squeezed for time to set the long range tests up.
You've got ejector pin marks so you've exceed the yield point of the brass.
 
You've got ejector pin marks so you've exceed the yield point of the brass.
Normally I’d agree, but everything does it, even the lowest starting charges and factory ammo.

There’s no expansion above the extractor groove until 78 gr with the 208, and 76 grains with the .225. The 208 load peaked at .0004 expansion, and the 225 load at .0006. Pretty soft loads by those measurements. Hodgdon considers max .0008. I’ll keep an eye on it though, and I dont plan on pushing past these charges I reached today.
 
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