6.5prc to 7saum conversion?

[Pudgy]

Once you've processed your brass have you tried chambering it before loading powder and a bullet to see if it chambers? Any problems with extraction on the virgin brass once it's fired?

Figured out the issue. I have a tight neck. The virgin brass neck thickness was .0145, once fired brass .016. I turned the necks and rounds feed flawlessly.
I've never had neck thickness increase before and not sure what caused it.
1 issue I haven't figured out yet is whats causing the once fired unturned brass to get a crease at the shoulder/case union and marks on the shoulder.
I'm going to run a borescope and see if I can figure it out.

 

[7.62 Gunner]

Figured out the issue. I have a tight neck. The virgin brass neck thickness was .0145, once fired brass .016. I turned the necks and rounds feed flawlessly.
I've never had neck thickness increase before and not sure what caused it.
1 issue I haven't figured out yet is whats causing the once fired unturned brass to get a crease at the shoulder/case union and marks on the shoulder.
I'm going to run a borescope and see if I can figure it out. View attachment 399011View attachment 399012

Yeah that's a tight neck!
I always go for .004-.006 neck clearance.
I think the shoulder might be getting scratched on the feedramp or ejection port, I've seen the same thing and it's no big deal

 

[gregsjt]

Wrong again...almost.
It is a very well known issue. Tons of factory rifles and custom rifles have the issue.

So much so, that Alex Wheeler came out with a reamer design to clean up a SAAMI chamber and fix the problem. For both the 6.5PRC and the .300PRC. I hope Hornady figured this out and doesn't make the mistake yet again with the new 7PRC.

OK, I want to be clear up front, I'm not trying to argue, I really want to get to the bottom of this. Here are my questions / comments:

• Are reamer's cut to the dimensions listed in the SAAMI specs for chamber dimensions? For example, when you look at the below picture the first drawing is the case dimensions and the second drawing is the chamber dimensions, is the second drawing the basis for the reamer design?

• If the answer to question 1 is yes, and reamers are cut to the spec's laid out on the SAAMI cut sheets. How are the PRC cases different from the other cases listed below? Why are most of the popular cartridges designed the same way? Almost all have .001 (+/- .0001) difference between the cartridge diagram and the chamber diagram at .200 from the cartridge base. The only exceptions are the WSM cases and the 338 Lapua.

Case	Cartridge Dimension @ .200	Chamber Dimension @ .200	Difference
7mm WSM	0.5550	0.5563	0.0013
33 Nosler	0.5500	0.5510	0.0010
338 RUM	0.5500	0.5510	0.0010
7mm SAUM	0.5500	0.5510	0.0010
300 PRC	0.5320	0.5330	0.0010
6.5 PRC	0.5320	0.5330	0.0010
338 RCM	0.5320	0.5330	0.0010
338 Lapua	0.5854	0.5873	0.0019
26 Nosler	0.5500	0.5510	0.0010
300 WSM	0.5550	0.5563	0.0013
375 Ruger	0.5320	0.5330	0.0010
300 Win Mag	0.5126	0.5136	0.0010
7mm Rem Mag	0.5127	0.5136	0.0009
6.5 Creed	0.4703	0.4714	0.0011
260 Rem	0.4703	0.4714	0.0011
270 Win	0.4698	0.4708	0.0010
7mm-08	0.4703	0.4714	0.0011

So, final question: If Hornady botched the design of the PRC cases or reamers, why is the difference from cartridge to chamber the same as all of these other cartridges?

I guess the most pressing question is, if the design is the same or similar, why are we seeing "clickers" with PRC cases and not all of the others?

Thanks!

 

[lancetkenyon]

I think the biggest issue is the reamer used to cut the dies is not quite small enough. Not enough differences between the SAAMI chamber and what the dies can size the fired brass down to.

Here are a couple good (long) reads for reference.

PRC SAAMI Chamber Issue - The JGS AW2 (Alex Wheeler) Finish Reamer Fix

Well guys, I finally got the bolt click on my bergara 300 prc. I am using lapua brass on its third firing. I have seen this wonderful post from fellow Ladd and it explains it wonderfully. I am going to buy the 300 prc Aw2 reamer and do it. I don't have tools to remove the barrel. Is there a...

www.longrangeonly.com

6.5 PRC Dies not sizing enough

M Checking back in. Appears I don't have PM privileges. Thank you. My 6.5 PRC reamer is due back tomorrow. I’m out of town until tomorrow night so let me check it out when I get back then I will reach out.

www.longrangeonly.com

6.5 Prc reloading

Ok I am reloading for my new gun and I have a question, I have purchased both the ADG brass and the Lapua brass to try so which one should be the first to try?? If the first one works great then selling the others. Thanks for any imput! Marc

www.longrangehunting.com