Bushing a firing pin

[Jeff Porter]

Negligible difference in SR Magnums versus standard match primer as far as brissilance of the primers. Mostly the cup thickness to hold up to higher pressures in my experience. Also R 71/2, CCI 450 and Fed 205 MAR are interchangeable with my loads.

Don’t stick a CCI 400 or Tula standard primer in there unless you really like primer flow and piercing.

 

[Shutstr8r]

I’ve never had to have a bolt face bushed in my 45 + years of shooting. Not that I don’t have a gun that could use it, but I try to find another workaround. Like backing down the load, or using a little bit slower powder. I would tend to agree about the magnums vs regular primers, however I did have an unusual experience recently with REM 7.5’s vs CCI 450’s that I’d like to share.
I was loading up a batch of ammo for the winter dog season, .223 Ackley, 26” bbl, with Berger 80.5’s and Ramshot TAC. I had 10 rounds with Rem 7.5’s and 10 with CCI 450’s and chronographed them on two different strings of fire (not a big sample). The CCI’s chrono’d 38 fps slower on every shot. Now I’m aware that Ball Powder is not necessarily the most consistent ignition. However, all the groups were some half inch just food for thought I still like my CCI 450s, but I was able to pick up 5000 of the REM 7.5’s for a steal from the granddaughter of a close friend that passed several years ago for what he paid for them. I think that I am going to use those in my 223 Ackley from now on. I still like the CCI 41s and 450s for my AR loads but I will conduct the same test with my small primer 6.5 and 6 mm Creedmoor.

—Darrell

 

[divingin]

This seems to be mostly an issue with 223 bolt face. The CCI 400 primer cups are thinner than the 450's and many times changing primers cures the issue. I have not seen the same issue with large rifle primers

I used to have problems with my 700 (308) with upper end loads (not over book max, but working the upper range.) Fairly severe cratering with standard CCI large rifle primers; no brass marking (I think I might have blanked a couple, which spurred the modification.) Having the pin bushed took care of the cratering, and I found I could (you should read that as "could, but generally don't") work to at least a grain or two over book max before I started seeing faint ejector marks on the case head. I quit chasing velocity after that, but remain a believer in the value of having the firing pin/bolt gap reduced.