350 Legend soot

[jims]

I have only 2 brands of cartridges here locally for my .350 Legend. The 180 grain Power Point Wins shoot slightly better than my Hornady (non flex tip). The Wins however leave soot and carbon streaks on the case nearly to the base. The Hornadys are clean.

The Win bullets are .354, the Hornady is .355. I think the cartridge headspaces off the top lip. I never have had factory ammo soot up like that, any thoughts? Thanks

 

[contender]

Usually,, when you get sooty brass,,, it's because the brass didn't expand enough to "seal" the chamber,, and you get a bit blowback burning gasses.

 

[Dan in MI]

I agree with Contender. I didn't answer last night because I think you have a unique situation over the usual "low pressure didn't seal" that will take a longer answer. I will expand some here.

First you have a Legend. There is a lot of discrepancy in the cartridge. Barrels have been bored for .357 and .355 diameter bullets. Final specs say .355 + .002" or .003 (can't remember exactly now) That gives you questionable bore diameter. (I'd do a chamber cast and slug the bore)

Second you have two rounds with different diameter bullets the smaller one gets sooty brass. The larger doesn't. That points to a bullet to bore fit causing low pressure and soot.

IMO your only option is to slug and cast the barrel, to find out what you have, and shoot bullets sized accordingly.

Being a .357 Maximum fan I was all ready to jump on board the Legend train until I learned of these issues. It's messy enough that I'm just sticking with my Maxi's. There is a thread here somewhere here with more detail on the specs and the related issues.

 

[Mobuck]

Could be a combination of smaller bullet diameter and "harder" brass. Maybe a quick and easy chrony check will give you an answer. I never felt good about the "bore slugging" procedure especially on a rifle length barrel.

 

[contender]

Dan may well be onto something.
I have ZERO direct experience with the 359 Legend. I'd follow his thought direction if I were you.

Mobuck also makes a valid point. Small bullet,, harder brass,, and such.

But you can slug a barrel,, even in rifles.

 

[TX Nimrod]

Sooty brass is caused by gas blowby before the case expands enough to seal the chamber. Experienced reloaders know that this could be caused by either a slow powder, a low pressure load, or tougher/thicker brass. A bullet diameter difference of 0.001" won't do it.

But who really cares? It is only a cosmetic issue as long as the cartridges function as needed. If it really bothers the OP he can just use the Hornadys. Problem solved.


.

 

[Ethang]

What rifle are you shooting? I think Dan is right and the rifle that you are using and the bore diameter vs bullet diameter is what is causing the soot. You might be seeing some tolerance stacking going on with a large bore spec vs small bullets. If it is shooting well and does what you need I wouldn't worry about it though. My 45 Colt is sooty but does what I want it to.

I have been following the 350 Legend since it came out, bought all of the materials to load for it, but have not purchased a rifle as of yet. Still on the fence about what platform I want to go with. I really like how handy the little Ranch rifle is, but love my Encore that I have had for years.

 

[Dan in MI]

Sooty brass is caused by gas blowby before the case expands enough to seal the chamber. Experienced reloaders know that this could be caused by either a slow powder, a low pressure load, or tougher/thicker brass. A bullet diameter difference of 0.001" won't do it.

But who really cares? It is only a cosmetic issue as long as the cartridges function as needed. If it really bothers the OP he can just use the Hornadys. Problem solved.
.

Somehow I get the feeling this is a directed response with a bit of holier than thou attitude. If I am wrong, I'll apologize now.

Experienced reloaders also take into account other factors. Especially with a cartridge known to have variations. If the bore is a .357/.358 as many are, and the bullet is a .354 there's .004" available for blowby and reduced pressure. And of course, we all know factory bores are always at spec so there could never be a case of a little over bore either.

 

[jims]

Just to answer the question of the rifle. It is a new Thompson Center Venture II bolt action. For a factory trigger it is pretty good. One of the reasons I bought it over other brands.

 

[Ethang]

Just to answer the question of the rifle. It is a new Thompson Center Venture II bolt action. For a factory trigger it is pretty good. One of the reasons I bought it over other brands.

I follow a couple 350 forums and have not heard about this particular soot issue, and have not heard of anybody with that rifle though either. Interesting issue. Maybe the chamber was cut on the large side of the SAMMI spec. Have you inquired with TC about the issue?

 

[recumbent]

I picked up about 20 350 legend cases at the range today and every one had black soot on the entire case.
I don't have a 350 so i throw the cases in my scrap bucket.

 

[jims]

Blackhawk, do you know what brand(s) they were?

 

[recumbent]

I just looked, they were all winchester brass.

 

[jims]

Thanks for the quick reply. That is the brand that I had the soot on also. I think I am going to stick with the Hornady brand that does not do that.

 

[Justice B. Swift]

Another thought...
Awhile back I was having this issue with a "soft" cowboy load in my 45 Colt. I learned two things and solved the issue.
1) my Dillon press sizes my cases slightly smaller than my RCBS dies do. Smaller cases add tension to the seated bullet helping to increase pressure.
2) a firm crimp (as opposed to none) allowed the pressure to increase to a greater level before releasing the bullet.
For my situation sizing in my Dillon and adding a bit of crimp solved all shooting issues completely.

For your situation it was mention that bullet diameter vs. barrel diameter may be of note, but small bullet diameter will also influence case fit (pressure) as well, as noted above. And factory crimps can (and do) vary greatly. Just a couple thoughts.