punctured primers

[ragenmoan]

Using some British surplus Radway Green 4895 powder, to hand load .223 for my 20" barrel length AR 15. After about 500 rounds, I am starting to now see perforated (punctured) primers.

I'm loading 69 grain Sierra HPBT, 25.5 grains of RG4895 and CCI primers (not the thick skinned ones). This RG4895 powder is suppose to be close to IMR4895 so I'm using charge tables for the IMR4895. I am still using the same 8lb container of powder and primers from the same "brick" of 1000. The powder scale calibration has been checked to be OK and the bullets weigh OK.

Per articles I found on the internet, I found the firing pin protruding through the bolt too much (either because the pin was too pointed or the bolt pin hole was too big) and replaced both the bolt and firing pin with new ones.

I thought replacing the firing pin and bolt would fix the problem but it hasn't. Anybody have some ideas why using the same box of powder and charge, same lot of bullets and primers could suddenly appear to be overpressurizing?

I'm looking to try new brass and lower powder charge if I have to but this load works really good in My AR.

[buffybuster]

Have you tried reducing the powder charge?

Any pull-down powder burnrate is going to vary from canister grade equivalent. Hodgdon/IMR website shows your charge weight being right near MAX.

[Hans Gruber]

Two things come to my mind:

1) The powder may be temperature sensitive. Now that we're into spring/summer temps, the powder is creating more pressure at the higher ambient temperature.

2) Your chamber may be dirty, due to insufficient cleaning regimen, causing a tighter fit for your brass and thereby higher pressures.

Just off the top of my head.

Good luck!

[Ahhnother8]

The powder may be temperature sensitive. Now that we're into spring/summer temps, the powder is creating more pressure at the higher ambient temperature.

Likely this. And dump the CCI 400 primers and go with 450's or BR's.

[ragenmoan]

Two things come to my mind:

1) The powder may be temperature sensitive. Now that we're into spring/summer temps, the powder is creating more pressure at the higher ambient temperature.

2) Your chamber may be dirty, due to insufficient cleaning regimen, causing a tighter fit for your brass and thereby higher pressures.

Just off the top of my head.

Good luck!

Gonna first giving the rifle a good clean. Could the primer cap extrude through the bolt's firing pin hole because the spent brass is not ejecting properly? Could a clogged gas tube also cause this problem? I'm assuming if the brass sticks, as the barrel pressure builds up before the bullet exits, some of the pressure has to be relieved and in this case, through the firing pin dimple imprinted on the primer.

Will need to reduce powder charge if the cleaning does not fix the problem.

[phish]

I'm loading 69 grain Sierra HPBT, 25.5 grains of RG4895

way too hot a charge with a *.4895 powder, probably even pushing it with that much Varget or RL15 imo

[FLIGHT762]

My Sierra #5 manual shows 24.5 of IMR 4895 as max for the their 69 gr. OTM.

My Hornady 7th edition shows 24.9 IMR 4895 as max with their 68 gr. OTM.

Both of these data were shot in 20" barrel service rifles(AR-15).

You are using a British Military surplus powder, NOT IMR4895.

Try backing off a full grain and see if you're still getting pierced primers. You can also run your loads over a chronograph. If you're getting over 2800 F.P.S. in a 20" barrel., your load is too hot(that is my guess).

By the way, I'm also using the RG4895, but in a .308 Win. I haven't tried it yet in my .223 Rem rifles.

[ragenmoan]

Thanx all for your support. I'll need to revisit my load data for sure since I am unable to find any tables specifically for the RG4895. The info on the internet suggest that it's suppose to be close to IMR4895.

Flight762
I'm looking to use this powder for my 18" and 24" LR308s also. How is this powder working for you? What types of bullets and charges have you tried?

[FLIGHT762]

I'm getting .75 MOA or a bit better using 43.0 RG4895 using the Hornady 168 OTM and A-MAX.

I started out using 41.0 GRS. and worked up to 43.0 from there.

I'm using Hornady TAP brass and Wolf primers. No signs of too much pressure. Load shot well out to 550 yards and tracked about the same as factory 168 match. Shooting it out of a Rem. 40XBKS with a 27 1/4" barrel.

I'm using 42.0 RG4895 with Nosler 175 OTM's with good results. I've only fired about 20 test loads so far with the 175's. I'll be doing more testing with the 175's.