300 PRC update

Rocketmandb

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I just found two pounds of Reloder 26! Hopefully it will come back into regular supply again, but at least I can play with this for now. I have RL33 on order to do the same. I'm also going to try some lower loads of Retumbo this weekend. Will post results.
 

LakuNoc

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Thank you for input. Rifle will be:
Mausingfield ARC action
Proof CF barrel 26 Inch
Tangen Theta 5-25x56 Gen 3XR Scope
Manners or KRG Whiskey-3 Chassis with folding stock
Spuhr Mount
Heathen Muzzle Brake

Should be Around 12.4 LBS
I think it would be okay for hunting. I will be taking rifle 3-5 miles hikes but i think I'm okay with 12.4 LBS
 

doctordoctor

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I just found two pounds of Reloder 26! Hopefully it will come back into regular supply again, but at least I can play with this for now. I have RL33 on order to do the same. I'm also going to try some lower loads of Retumbo this weekend. Will post results.
Where did you find it?
 

Rocketmandb

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Update on Hornady FL resizing dies:

I ordered another Hornady resizing die and just resized 56 cases. Why 56? Because I wanted 50 appropriately resized cases and this is how many it took to get there. Of the 50, about 1/3 were showing as 1/2 a thousandth low - this is marginally acceptable, and it could just be that the case is sitting on the fence between the lower 1/2 thousandth and higher. All of the six inappropriate cases were 1 thousandth low, so this is significantly better than the last die.

All the other components remained the same - same shell holder, same press, same lube.
 

b2lee

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Dec 30, 2018
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Retail box of 300 PRC 225gr ELD-Match in a AICS Long Action 338 Lapua Magnum CIP 5 round steel mag.



And then focused on the tip to the end of the front of the magazine



This particular round is showing 0.0675 clearance.
 

motofrog

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Retail box of 300 PRC 225gr ELD-Match in a AICS Long Action 338 Lapua Magnum CIP 5 round steel mag.



And then focused on the tip to the end of the front of the magazine



This particular round is showing 0.0675 clearance.
How’s feeding out of the 338 lapua cip length mag compared to the 300wm cip length mag?
 

b2lee

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How’s feeding out of the 338 lapua cip length mag compared to the 300wm cip length mag?
They push out with my fingers just fine...heh...I'm still in the process of having my barreled action made....

I don't have a 300wm CIP mag though. I know...I'm no help at all...still waiting on brass to hit the market too.
 
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LakuNoc

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Wondering where i can get Proof CF barrel chamber in 300 PRC. Savage small/regular shank for my Mausingfield action?
 

Kickin45

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So I’m trying to get a barrel built, but my barrel guy won’t go lower than 1-9.75 twist.
What’s everybody running on their 1000yrd plus rifles?
I asked for 9.25 or even 9.5 twist.
Thanks in advance guys
 

Kickin45

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I know they do. Paul ordered me a Proof Carbon Fiber 300 PRC Savage Prefit as well as an Proof AI AXMC 6.5 PRC steel prefit. Call him and he will take care of you.
Do you know if he does custom twist rates and Desert Tech barrels?
 
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Ledzep

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So I’m trying to get a barrel built, but my barrel guy won’t go lower than 1-9.75 twist.
What’s everybody running on their 1000yrd plus rifles?
I asked for 9.25 or even 9.5 twist.
Thanks in advance guys
1:10 will cover most anything on the market right now up to 230gr. May be on the edge with some of the super heavies. I went gain twist 1:9.5 to 1:9
 
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Dschapp44

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1:10 will cover most anything on the market right now up to 230gr. May be on the edge with some of the super heavies. I went gain twist 1:9.5 to 1:9
Hopefully the 9 twist will pay off if Berger gets the 245 EOL to market.
 

Rocketmandb

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Update from the range:

I ran two sets of work ups today. One with a retry of Retumbo (see below as to why) and one with seating depth using my current "champion" load of 76.2 gr H1000. The second set was seating depth at 2.5, 5, 7.5, 10, 12.5 and 15 thousandths off the lands. I also sighted in and used my new Razor HD 4.5-27 for the first time - quite happy with it.

First the Retumbo: after returning from my last time out, I noticed that two of the screws on my rail were loose - think that had something to do with my accuracy issues? So I decided to retry Retumbo. This time I started at 76.1, and went up to 77.3 at .3 gr increments.

All groups were 4 shots at 200 yards using ELD 225

76.1:
Group: 1.07"
Average: 2846
ES: 12
SD: 5.6

76.4:
Group: .76"
Average: 2860
ES: 15
SD: 7.0

76.7:
Group: 2.01"
Average: 2863
ES: 21
SD: 8.6

77.0:
Group: 1.15"
Average: 2886
ES: 32
SD: 11.5

77.3:
Group: 1.22"
Average: 2892
ES: 21
SD: 9.5

I'm liking the 76.4 gr Retumbo load quite a bit. I'll probably pit it against the 76.2 gr H1000 load next time out and see which wins.

On the seating depth test, one group stood above. It had one flyer that took the group size out to 1.08" - but the other three were touching with a group size of .355" center to center. The average velocity as 2866 ft/s, ES of 5, SD of 3.6. This seating depth was 12.5 thousandths off the lands.

Rifle with the new scope (albeit temporary until my new build gets done):

7060745
 

BirdHunter91

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Sep 24, 2018
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My 300prc rifle got put on hold while I dilly dally with other fun things. Any interest in 5 boxes of hornady match ammo?
 

b2lee

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If you had just brass...I'd be interested...

5 Boxes of match seems to be more than all the retail places combined....so yours should go quickly since the market is bare.
 

186thFCo

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Just ordered my barrel from Bartlein for my 300 PRC, it will be a M24 contour, fluted, 5R rifling 1:8.5 twist and will finish at 28” I just wish there wasn’t a 5 to 6 month wait time.
 

Dippy

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Just ordered my barrel from Bartlein for my 300 PRC, it will be a M24 contour, fluted, 5R rifling 1:8.5 twist and will finish at 28” I just wish there wasn’t a 5 to 6 month wait time.
I got mine in less than 6 weeks! But now on the waiting list for my 300 win mag replacement barrel.
 

Ledzep

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Was about 5-6 months for mine. Just got it last week. I believe I ordered it in October/November timeframe.
 

Dippy

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They told me 6 months when I ordered, but called me a few weeks later and said they had my barrel, and that it must have been one that came in from a show or someone didn’t pay, regardless it’s at Dave Tooleys shop getting spun up in 300 PRC.
 

doctordoctor

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I don't have a ton of time to post but I went out for round 2 with my 300 prc.... More or less frustrating. The used brass that was 1x fired in my gun last round still caused ejection issues. However the 10 pieces @Rocketmandb donated to the cause all worked flawlessly! So it must be a brass issue as suspected. So it wasn't a complete waste of a trip to the range. My velocity was around 2850 using 74.8 grains of H1000. 225eldm bullets. Cci250 primers. All 10 rounds fit into a quarter

So if my brass would show up and i could find powder and primers... I'd be more than happy.
 

AlBundy81

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Noticed most of the 300prc are running a 1:9 twist. I saw where Barrett is coming out with barrels for the MRAD in 300prc at 1:8 twist 26” barrels. Thoughts?
 

Ledzep

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Akin to the 1:7 or 1:8 debate with 77gr .223 projectiles. Both work, one spins them slightly faster. I don't think twist rate is something to get caught up about unless you're on either end of the extreme-- blowing up projectiles, or having them hit paper sideways.
 

Rocketmandb

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I'm not going to get out to do more load development this weekend due to business travel during the week and no time to reload. I do plan a long session the following weekend, and would like to try out some RL33, but load data is hard to come by. Does anyone have a good starting point for 300 PRC? I probably won't shoot much of it, just a few loads to cover a wide spread to get an idea on velocities.

EDIT: Will be shooting 225 ELD
 
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Harleydog

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Dec 6, 2018
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Have my 300prc all together and working good. 26” Bartlein m24 barrel. Broke in with hornady match 225g. Then shot a few groups with the factory 225g. .4 MOA groups. Loaded some rl26 from 74.4-75.6 with 225eld. Didn’t work very good. +1 moa. Using 215m primers. I pulled 3 factory bullets and weighed 74.0g from each. Thinking I may need to work down from 74.4 to 73?
 

TripleBull

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I don't have a ton of time to post but I went out for round 2 with my 300 prc.... More or less frustrating. The used brass that was 1x fired in my gun last round still caused ejection issues. However the 10 pieces @Rocketmandb donated to the cause all worked flawlessly! So it must be a brass issue as suspected. So it wasn't a complete waste of a trip to the range. My velocity was around 2850 using 74.8 grains of H1000. 225eldm bullets. Cci250 primers. All 10 rounds fit into a quarter

So if my brass would show up and i could find powder and primers... I'd be more than happy.
But, what is the answer? Rocketmandb's brass shows that your rifle has very good accuracy potential, so what will you do differently once you have the brass, powder and primers?
 

Harleydog

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Dec 6, 2018
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Having sticky bolt on reloads. Comes up fine but hard to get back without big effort. Case necks turned and trimmed to factory spec. Factory ammo runs great. Ideas?
 

Harleydog

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Dec 6, 2018
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Anyone else running rl26? Getting pressure issues starting around 73g. Gonna work up h1000 and see where that’s at. Gonna start around 74.5 and go up? 26” 1:9 twist.
 

nick338

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Anyone chambered a 300 PRC off a JGS reamer yet? Just curious how they compare to the other reamers out there now.
 

Rocketmandb

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Anyone else running rl26? Getting pressure issues starting around 73g. Gonna work up h1000 and see where that’s at. Gonna start around 74.5 and go up? 26” 1:9 twist.
I will be doing some testing with RL 26 this weekend. I've got a 28" 1-9 and all my data from load testing is in this thread. My current "champion" load with H1000 is 76.2 with the 225. I did a bunch of H1000 testing above published maximums, and started seeing sporadic pressure signs about 1 gr above.

Questions:

- What bullet were you pushing where you were seeing pressure issues at 73? EDIT: Just saw that you were using 225s. That seems very low.
- Is this a new rifle/bolt? EDIT: It looks like a new rifle from your posts. What action/bolt?
- What pressure signs are you seeing?
 

doctordoctor

El Doctor
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Having sticky bolt on reloads. Comes up fine but hard to get back without big effort. Case necks turned and trimmed to factory spec. Factory ammo runs great. Ideas?

Welcome to the club! I am waiting for new brass.

I checked the used brass I was using versus the new brass @Rocketmandb sent me... They are the same case volume! I'm getting 96.5 grains of water.

My only guess is I am over pressured with my loads... Except the same load as the new brass I used was sticky.

I hope that makes sense.

I need my brother to throw my data into quick load. The gun and cartridge has so much potential... I'm just not squared away yet.
 

DAVETOOLEY

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I was just asking mainly for inconsistencies between manufacture's reamers referencing several issues that have come to light with the 300 PRC in the last few months.
I don't think we know "The rest of the story" about most of those issues.. I've been chambering it for 12 years now and have had probably 6 different reamers in that time. Each for a specific purpose. No problems that weren't self inflicted. Now it is standardized. The reamer manufactures I use hold tolerances -.0000" + .0005" Those are JGS and Manson. Manson for HSS and JGS for carbide. Very happy with both.
 
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Ledzep

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One thing people need to understand about Hornady brass is that you just can't hot rod it. It's perfectly fine if you stay under 65ksi (And I'm not going to say an especially soft lot never makes it through). If you're running on the upper end and something causes a spike (piece of carbon fell down the muzzle from your suppressor/brake and got in the neck area, for example, or carbon builds up in the throat or neck), then the cases exceed the yield strength and plastically deform. Primer pockets open up, sticky bolt, etc... I believe that's largely the problem with the GAP 4s brass they make/made. Some sort of interference between the brass, sizing die, and the chamber that makes pressure spike. I do believe the 1st lot of 4s brass got an over zealous annealing cycle, though.

The other thing could be a die sizing issue. That's as simple as doing a cerosafe mold of the die and micing it out to see if it's doing what it's supposed to. In that event, the BEST thing you can do is let whoever made it know so they are aware and can address it.

All teething problems that happen with anything. Don't buy the first year of production of any vehicle, motor, etc... etc... if you're not willing to accept the risk of some unforseen issues.
 

nick338

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I don't think we know "The rest of the story" about most of those issues.. I've been chambering it for 12 years now and have had probably 6 different reamers in that time. Each for a specific purpose. No problems that weren't self inflicted. Now it is standardized. The reamer manufactures I use hold tolerances -.0000" + .0005" Those are JGS and Manson. Manson for HSS and JGS for carbide. Very happy with both.
Correct, that's exactly why I made no mention of names on anything related to the issues I have heard of because we don't know the whole story start to finish and just "suspicions" on what may have been causing them. I have a tendency to over-think things sometimes and try and prevent a problem before it starts. Unfortunately is has become part of the process after years of doing this and not doing the proper research beforehand and wasting a lot of money along the way.
 
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DAVETOOLEY

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Correct, that's exactly why I made no mention of names on anything related to the issues I have heard of because we don't know the whole story start to finish and just "suspicions" on what may have been causing them. I have a tendency to over-think things sometimes and try and prevent a problem before it starts. Unfortunately is has become part of the process after years of doing this and not doing the proper research beforehand and wasting a lot of money along the way.
Understood