300 PRC update

SRPowah

Gunny Sergeant
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Feb 13, 2017
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Peoria, IL
I just received my Proof Research small-shank pre-fit in 300 PRC and the Hornady Match and Hunter factory loads both feel like they're jamming into the lands when I slide them in the chamber by hand. I could send it back to Proof, take it to a gunsmith and have the throat lengthened, or just leave it. Any other thoughts or suggestions?
Call Proof first and see what they say.
 

Ledzep

Chancellor
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Jun 9, 2009
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Do you see marks on the bullets or are they hard to chamber? Could be tight headspace.
 

doctordoctor

El Doctor
Belligerents
Apr 30, 2011
338
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Erie,pa
Ok gang I finally found a morning to shoot. It was hot and the mirage was like the Sahara desert! But here is some load data with hornady new brass and RL26.
Gun is a DT
Barrel is 30" spun up by Dane @DMR rifles
Amax 225gr
Cci 250
3.66" COL

74gr = 2908
74.4 = 2920
74.8 = 2940
75.2 = 2960
75.6 = 2969
76 = 2992
20190703_162758.jpg
 

Rocketmandb

Private
Minuteman
Nov 2, 2018
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I just took a quick trip down to the local 100 yard range and shot this 4-round group:

7106064

Why is this post-worthy?

It was with pre-fire-formed 8x68S brass. There's something about getting half-MOA or less (center to center) with cases that don't fit your chamber.

For those who are interested, I will be posting two videos in the next few days that go into why the 8x68 works so well, considerations during case prep, and then what process I go through to ready the cases for fire forming.
 

Rocketmandb

Private
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Nov 2, 2018
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Are you using 8x68s Norma or RWS brass?
I have both, primarily because I found a bunch of Norma on sale, but I'm saving the Norma for later. Right now I'm concentrating on the RWS.

I was hoping to do a ladder with it this weekend, but this week sucked, and I didn't have time to load. It has less volume than Hornady, so runs hotter. A few weeks ago when I was playing around the upper end of the scale with RL 26 with I was getting 3000+ fps with 75.2 gr (225 bullet).

I've decided that I don't want to play there any more, and I think my barrel has a sweet spot at 2850 fps-ish. That's the realm where my H1000 load of 76.2 gr lands. I'm going to start the ladder at like 73 gr of RL 26 and find 2850 with the RWS.

The long and the short of it is that I'm sold on 8x68S. I go through everything in the videos I'm working on (part 1 is done, part 2 in work - 2-video series), but the nice thing is that there's not a significant amount of additional prep. After I get the neck all set, I'm seeing less than a thousandth variation - and the primer pockets... I've said this before, and I know it's weird to get some kind of zen feeling over primers, but it feels so nice to have real brass to seat primers in again.

I think you guys will like the videos. I'm starting a channel and web site called Two Minutes to Target where I do videos and short posts on all things precision. A pet peave of mine in the shooting world (one of a number of them) is that so many of the videos are way too long. So every thing I do will be under three minutes - hence why I had to split this one into two. These two are the inaugural vids.
 

jasent

ELR junkie
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Jan 23, 2013
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I’m glad some one finally realized the 8x68s brass was a good option. My first batch is on its 10th loading and pp are still nice and snug. My loads are rather hot and I’m shooting the 300gr bergers at 2750 with my 338/375 improved and 82gr h1000. The RWS brass is slightly better than the Norma.
 

Rocketmandb

Private
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Nov 2, 2018
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I’m glad some one finally realized the 8x68s brass was a good option. My first batch is on its 10th loading and pp are still nice and snug. My loads are rather hot and I’m shooting the 300gr bergers at 2750 with my 338/375 improved and 82gr h1000. The RWS brass is slightly better than the Norma.
For me it was a time thing - I didn't want to put in the effort to learn all the ins and outs. But then I finally just had it with the Hornady brass... and I got my Forster trimmer with the .308 reamer attachment and that made it a ton easier to get the necks uniform.
 
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Ledzep

Chancellor
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Yeah I would call Proof then. Shouldn't be an interference fit on the bullet.
 

JMattJ

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Minuteman
Dec 10, 2018
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I went with the 300wm 3.850 mags. The latest MTD mags I got from them work well. Had an issue with a few older ones but are being replaced. The latest ones work without issue. Accurate 300 win 3.850 also worked well. I had so slightly sand the inside of the lips to get it to feed a little smoother. Little tweaking pending what rifle and bottom metal is not out of the ordinary.
If you have the time, would you please provide more detail on where you had to sand the Accurate 300 WM 3.850 mags? The last round doesn't wan't to feed on mine either.
 

Rocketmandb

Private
Minuteman
Nov 2, 2018
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I just added my two-part video to Youtube on fire forming 8x68S for the 300 PRC. The instructional parts total only about six minutes in total, then I add a minute or so of range footage.

I highly recommend going this route. Here are the key points:

- It doesn't take a ton more time to prep an 8x68S case for the 300 than it does a Hornady 300 PRC case. You have to do one extra sizing, more trimming, and the inside neck turning (reamer).
- I fire these fire forming loads for fun and they're accurate.
- RWS cases come in at about $42 per 20, so they're not cheap. However, they are far more consistent and (I hear) will last a lot longer. I got Norma brass on sale for half that.
- The Forster trimmer and reamer I use during prep will run under $200 with shipping.

Part 1:

Part 2:
 

jasent

ELR junkie
Belligerents
Jan 23, 2013
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well worth the time. It’s great brass! With a slight edge going to the RWS. Norma is like night and day difference between hornady.
 

DAVETOOLEY

Gunny Sergeant
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Jun 14, 2009
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Oriental, North Carolina
Has anyone had issues with the smaller diameter rim?
I've run RWS 8X68 brass for over 20+ years in a .532" bolt face. The caveat is in bolts with m16 or Sako extractors there may be an issue with the case kicking out from under the extractor as the case clears the chamber and impacts the side of the action. Probably won't be a problem but it's possible.
 

Rocketmandb

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Nov 2, 2018
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Has anyone had issues with the smaller diameter rim?
Does not affect me during extraction. One thing to note is that the shell holder is a little different, so it can affect certain actions you take during prep and loading. Here's where it affects (or doesn't) my process:

- Reloading Press: Doesn't affect me here because you can get a shell holder from RCBS (#34)
- Trimming: Doesn't affect me because Lyman has a very cool rim holder as a part of their trimmer that doesn't care what size the rim is (within limits, of course).
- Neck Turning: This is an issue for me if I use the K&M because they don't have a shell holder to match, and you can get a little off center with the case. However, if I use my Forster trimmer to neck turn, it's not an issue. The .532 collet for the Forster can squeeze down enough to hold effectively.
- Priming: I use the 21st Century hand primer, and it doesn't have the appropriate sized holder. However, I have not found this to be an issue - it's priming, after all, and once the primer finds the pocket, it goes in smoothly.

EDIT: If you're concerned about this (I was), do what I did and order a single box of brass. Run one through your sizing die with the largest ~.33x bushing you've got (no expander ball!), trim to length, then put it into your chamber and test extraction a few times.
 
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Dschapp44

Gunny Sergeant
Hessian
Belligerents
Minuteman
Oct 15, 2018
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I just added my two-part video to Youtube on fire forming 8x68S for the 300 PRC. The instructional parts total only about six minutes in total, then I add a minute or so of range footage.

I highly recommend going this route. Here are the key points:

- It doesn't take a ton more time to prep an 8x68S case for the 300 than it does a Hornady 300 PRC case. You have to do one extra sizing, more trimming, and the inside neck turning (reamer).
- I fire these fire forming loads for fun and they're accurate.
- RWS cases come in at about $42 per 20, so they're not cheap. However, they are far more consistent and (I hear) will last a lot longer. I got Norma brass on sale for half that.
- The Forster trimmer and reamer I use during prep will run under $200 with shipping.

Part 1:

Part 2:

Thanks for the videos. My only question was why use an interior neck reamer then pushing it to the outside and use something like a 21st century tool?
 
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jasent

ELR junkie
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Jan 23, 2013
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I think you could easily push it to the out side and neck turn. I never had to do this with my 338/375 xl because I lengthened the head space 30k so I just had to neck up to 375 and back down to 338 to form a false shoulder. Then fire form and load em. Either way works and in the end you get the same results.

I did have extraction issues after a while but due to my extra long headspace and not the smaller base. I was sizing the case with a 375 ruger die with the expander removed. Wasn’t able to size down that last 30k. Modified my die and now have zero issues
 

Rocketmandb

Private
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Nov 2, 2018
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Thanks for the videos. My only question was why use an interior neck reamer then pushing it to the outside and use something like a 21st century tool?
I find using the reamer quicker and much easier to do. I played around with the K&M, but the shell holder difference caused me problems with wobble. I also played around with the Forster neck turning attachment, but you have to take off a fair amount of brass close to the neck, and I was having a hard time gauging exactly where to stop. I didn't want to end up with a donut on the inside and end up having to ream out anyway.

With the reamer, it's a quick and easy process. You're left with a neck that still has a very small amount of variation, but if you want to take 1/2 a thousandth or so off 50% of the exterior to even everything out, it's straight forward and less apt to cause issues.

As to the 21st Century tool, I've never used it, but it looks like a great unit. I've thought about buying one a few times, but the price always pulls me back. With the shell holder, I'm not sure which one would fit.

It's one of the things I like about the Forster tool: The smaller rim size of the 8x68S doesn't really matter. The .532 collett will shrink down enough to grab hold of the .512" rim (barely), and you can always order a custom collett from Forster if you want (I don't think I need to).

With all that said, if you can make an exterior neck turner work for you, then putting the case through an expander die after initial sizing then doing an exterior neck turn will work well.
 

Dschapp44

Gunny Sergeant
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Oct 15, 2018
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Awesome. Thanks for the reply’s. Just got my 300 Sherman mag back from the gunsmith and should have my 375 ruger should be in next week. I have hornady brass for both but this looks to be the better option for both. I emailed ADG and they said they have no plan to produce either at this time
 

Dschapp44

Gunny Sergeant
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Oct 15, 2018
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I find using the reamer quicker and much easier to do. I played around with the K&M, but the shell holder difference caused me problems with wobble. I also played around with the Forster neck turning attachment, but you have to take off a fair amount of brass close to the neck, and I was having a hard time gauging exactly where to stop. I didn't want to end up with a donut on the inside and end up having to ream out anyway.

With the reamer, it's a quick and easy process. You're left with a neck that still has a very small amount of variation, but if you want to take 1/2 a thousandth or so off 50% of the exterior to even everything out, it's straight forward and less apt to cause issues.

As to the 21st Century tool, I've never used it, but it looks like a great unit. I've thought about buying one a few times, but the price always pulls me back. With the shell holder, I'm not sure which one would fit.

It's one of the things I like about the Forster tool: The smaller rim size of the 8x68S doesn't really matter. The .532 collett will shrink down enough to grab hold of the .512" rim (barely), and you can always order a custom collett from Forster if you want (I don't think I need to).

With all that said, if you can make an exterior neck turner work for you, then putting the case through an expander die after initial sizing then doing an exterior neck turn will work well.
I ended up getting one for my 22 creedmoor project and the price stung but the fact it uses angled blades to match the shoulder angle was the selling point for me
 

Harleydog

Private
Minuteman
Dec 6, 2018
35
16
12
I just added my two-part video to Youtube on fire forming 8x68S for the 300 PRC. The instructional parts total only about six minutes in total, then I add a minute or so of range footage.

I highly recommend going this route. Here are the key points:

- It doesn't take a ton more time to prep an 8x68S case for the 300 than it does a Hornady 300 PRC case. You have to do one extra sizing, more trimming, and the inside neck turning (reamer).
- I fire these fire forming loads for fun and they're accurate.
- RWS cases come in at about $42 per 20, so they're not cheap. However, they are far more consistent and (I hear) will last a lot longer. I got Norma brass on sale for half that.
- The Forster trimmer and reamer I use during prep will run under $200 with shipping.

Part 1:

Part 2:
Can’t find website. Can you send me link please?
 

BirdHunter91

Private
Minuteman
Sep 24, 2018
19
3
6
Finally got around to shooting the Christensen arms Masa in the ballistics lab at work. Shooting the factory Hornady 225 match. I got 2826, 2813, 2820fps. This is out of a 24" barrel. I'm pretty happy with the velocity as it's faster then what Hornady claims which is 2810. Group was right at 1/4". This was the first group out of the rifle. It has a total of 12 rounds fired.
 

nick338

Private
Belligerents
Feb 21, 2013
351
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Finally got around to shooting the Christensen arms Masa in the ballistics lab at work. Shooting the factory Hornady 225 match. I got 2826, 2813, 2820fps. This is out of a 24" barrel. I'm pretty happy with the velocity as it's faster then what Hornady claims which is 2810. Group was right at 1/4". This was the first group out of the rifle. It has a total of 12 rounds fired.
It would have been too easy for the factory ammo to work for me. To say I'm disappointed in the results is an understatement. Velocity was right around 2860 average out of a 26" which is what I was expecting but I didn't bother shooting more than 3 rd groups as they were 1" at 100 and the best I could muster at 600 was 5.5"

This was with an early lot of ammo. I know the seating depth was changed slightly by .015 since then but I'm not sure that would made that much of a difference. Going to give the A-TIPS a try and see what happens.
 
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BirdHunter91

Private
Minuteman
Sep 24, 2018
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6
It would have been too easy for the factory ammo to work for me. To say I'm disappointed in the results is an understatement. Velocity was right around 2860 average out of a 26" which is what I was expecting but I didn't bother shooting more than 3rd groups as they were 1" at 100 and the best I could muster at 600 was 5.5"

This was with an early lot of ammo. I know the seating depth was changed slightly by .015 since then but I'm not sure that would made that much of a difference. Going to give the A-TIPS a try and see what happens.
For me this will be a hunting rifle. I want to shoot the 212 ELDX factory ammo and see how it shoots. As of right now with the poor brass choice i'm not in a big hurry to reload for it. If the 212's don't shoot to my likings then I'll start reloading and see what the 212 ELDX will do or try something of the VLD variety a try. It seems factory ammo is easily to come by, local store had all of it I could want in both the 212's and 225's.
 

Dippy

Sergeant of the Hide
Belligerents
Minuteman
Jan 19, 2019
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71101537110154
She has arrived.

300 PRC
Tooley Custom Rifles Orion action modified to accept CIP length mags
30” 5R 9 twist Bartlein Barrel
MBM 5 port beast brake
TT special trigger

Special thanks to:
@DAVETOOLEY at Tooley Custom Rifles for building the barreled action and @Frank Green at Bartlein Barrels for setting me up with the correct barrel and recommending Dave Tooley for the Gunsmithing work!
 

Dschapp44

Gunny Sergeant
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Oct 15, 2018
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Just got my 300 Sherman mag back from the gunsmith. Barrel is 26 inches with a 1-9 twist. The picture is a 215 hybrid with the start of the boat tail at the base of the neck to fireform the brass next to a 300wm with the 215 seated .020 off the lands. Quite a difference and I’m excited to try the 230 otms and SMKs
 

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Rocketmandb

Private
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Nov 2, 2018
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Just got my 300 Sherman mag back from the gunsmith. Barrel is 26 inches with a 1-9 twist. The picture is a 215 hybrid with the start of the boat tail at the base of the neck to fireform the brass next to a 300wm with the 215 seated .020 off the lands. Quite a difference and I’m excited to try the 230 otms and SMKs
How do you like the automated powder measure attached to your FX 120 scale?
 

Dschapp44

Gunny Sergeant
Hessian
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Oct 15, 2018
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How do you like the automated powder measure attached to your FX 120 scale?
It’s the best investment I’ve made outside my CPS and giraud trimmer. I’m going to a two day match next weekend and was able to throw powder and seat 400 rounds in 2 1/2 hours two nights ago. The best part is variance in charge weight was within .04 grains for the whole batch.
 

Dschapp44

Gunny Sergeant
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Oct 15, 2018
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I know everyone has their personal favorites and I’m sold on the impacts but a LA TL3 with the CIP is about the perfect action to start with for one of these builds.
 

thesheepdog

Full Member
Belligerents
May 28, 2013
185
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DFW
Anyone running 300 PRC in a Savage long action? I know Savage are predominantly longer than 700 and wondered how they would do with CIP Mags
 

b2lee

Private
Minuteman
Dec 30, 2018
79
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N. KY
Yea...the stock is good to go....but what was the action originally for? They made 3 different cut outs on the mag port...to my knowledge.