Fouled / Dirty case necks after firing.

[Bandit320]

I have been shooting 300 PRC and I’m getting dirty case necks after I’ve fired the round. My load is Lapua brass (3rd loading, annealed prior to this firing), 84.5 grs LRT, 250 A-Tip. This is a published load in the Ramshot guide and I’m getting good velocity, 2860 fps. Don’t know if this matters, it’s a compressed load. I can’t load any more into the case with the throat I have.

Case was neck sized, expanded with a mandrel, and seated; all LE Wilson dies. Is this low pressure on ignition? Rest of case is clean. Also, SDs kind of suck; 18 - 20 is the best I’ve been able to get. Any ideas? Thanks for the help.

 

[straightshooter1]

I have been shooting 300 PRC and I’m getting dirty case necks after I’ve fired the round. My load is Lapua brass (3rd loading, annealed prior to this firing), 84.5 grs LRT, 250 A-Tip. This is a published load in the Ramshot guide and I’m getting good velocity, 2860 fps.

Case was neck sized, expanded with a mandrel, and seated; all LE Wilson dies. Is this low pressure on ignition? Rest of case is clean. Also, SDs kind of suck; 18 - 20 is the best I’ve been able to get. Any ideas? Thanks for the help.

View attachment 7951667

Since that burnt powder is not progressing past the neck-shoulder junction, it's not a low pressure issue. Sometimes is just about a particular powder being used. It could also be that area of the chamber is not as clean as it should be, resulting in the the burnt powder being deposited that way.

As for as SD's go, there are a few things that can be attributed to. What scale are you measuring your powder with? Now much neck tension are you using? What are you using to anneal with (maybe you're not getting a proper anneal)?

 

[OREGUN]

The carbon is fine. Seems to vary by powder (cleaner vs dirtier), might be related to trim length and chamber throat cut, nothing to worry about.

Bad SDs could be anything. Most likely in my opinion charge weight consistency and neck prep…tension/expanding/annealing, etc. In sort of order of importance: Try full length sizing, double check all the charge weights (no “throwing” a charge for this round). Weigh each one. Try a smaller or larger expanding mandrel by a thou either way. Try a different seating depth, longer if you can or a powder that doesn’t require a compressed load. Try a different bullet.

 

[Bandit320]

Thanks guys. I size it down with a .334 bushing then use a .307 mandrel. I throw, then weight every charge so I don’t think it’s that issue. I’ll try scrubbing the throat area and if that doesn’t help I’ll probably try some loads with Reloder 26. I’ve had good luck with that in my WM. I can’t seat the 250s any longer so I could try dropping down to the 230s.

 

[Precision Underground]

Are you sure you’re not over annealing? I’ve cooked some that ended up looking like that and they were bad to get really dirty on the necks.

 

[Lawnboi]

Do you ever clean your chamber?

 

[918v]

Thats how case necks normally look after firing.

 

[*Nine]

Are you shooting with a suppressor? When I shoot suppressed my cases look just like that... a lot of fouling on the outside of the neck and the rest of the case is nice and clean. Even unsuppressed you'll still see some fouling on the outside of the necks, but your pics make me immediately think of brass that's coming out of a suppressed bolt gun.

 

[Bandit320]

Are you sure you’re not over annealing? I’ve cooked some that ended up looking like that and they were bad to get really dirty on the necks.

We have a winner!

Yes I clean the chamber and I don’t shoot suppressed. I shot the same load through virgin cases today and they came out spotless. Nice shiny clean. When I set up the annealer it was with Hornady cases. I’ll have to reset it for the lapua. Thanks all.

 

[918v]

lol

 

[Bandit320]

Are you sure you’re not over annealing? I’ve cooked some that ended up looking like that and they were bad to get really dirty on the necks.

Did your case necks recover after being fired a time or two, or where they toast?

 

[MK20]

It's pretty hard to toast the necks. Drive on.

 

[Precision Underground]

Did your case necks recover after being fired a time or two, or where they toast?

They were pretty old so I just let them go when I suspected I toasted them. I figured wasting time and money loading them to see if I could make them shoot was an exercise in tail chasing. I can’t say for sure that’s what happened but everything went back to normal with new brass so I’m pretty confident.