soot on cases

T

tillroot1

Member
I started testing on my 1000 yard light gun today, .300 wsm. using Norma brass I loaded 65 grains of H4831sc and used CCI br2 primers, using 2 different bullets, Berger 210 vld and a new 210 Berger test bullet. The seating depth is very different, the non vld bullet needed to be seated out quite a bit further to touch the lands in my chamber barely leaving much of the bearing surface in the case compared to the vld. The non vld bullets shot very well but the cases took on alot of soot clear to the boltface covering the case all the way around. my question is is it logical to think that not enough pressure is made by seating the bullet out so far to seal off the neck to the chamber or am I over looking something else. the chamber is a .332 NK and my loaded round is .3295 it shoots the vld style perfect and it seals perfectly. thank you, Ron Tilley
 
65 grains should be making plenty of pressure to seal the body to the chamber but it does sound as though it is not. Have you checked the velocity over a chrony? You should be at around 2800 fps with that load. Any pressure sign? If no, I would slowly work up while watching for pressure, and see if it seals. Remember, common sense must be used as to how hot to go. --Mike
 
Mike thanks for the reply. the load worked perfectly to win a match a couple weekends ago, the only difference is the bullet but its the same weight and seated out way further. velocity is just under or at 2900fps. thanks again, Ron Tilley
 
I used to get soot back to the shoulder/body joint with a particular load where I had maybe .030" of projectile in the neck. I put that down to the primer popping the projectile out before the powder ignited enough to seal off.

Maybe yours is some of the same.
 
The non-VLDS are supposed to be capable of jumping, like the Sierra smks or Laupa Scenars. You may want to try backing the bullets off the lands by 0.010-0.020; it will give you better seating into the neck and may not hurt your results.

JeffVN
 
I would have to agree with John & Jeff.The pressure must rise to above 5000 psi before the bullet leaves the neck.

Chuck.
 
JeffVN said:
The non-VLDS are supposed to be capable of jumping, like the Sierra smks or Laupa Scenars. You may want to try backing the bullets off the lands by 0.010-0.020; it will give you better seating into the neck and may not hurt your results.

JeffVN
Click to expand...

I have done exactly this and also tightened up the bushing by .001 and will try it again today. thanks, Ron Tilley
 
I got soot on my cases a couple years back and found out I had a carbon ring in chamber.
 
I shot again today, first 5 bullets out of the tube were the vld type Bergers, then 3 groups of 5 of the non vld Bergers, no soot on cases with the vld but as soon as I shot the non vld bullets they started sooting, clear back to the boltface. I am sure its because of the bullet seated WAY out. It shot 3 5-shot groups in the mid .2s so I want to make it work. The problem is that I chronographed these loads and the velocity was from 2970fps down to 2686fps. any ideas how to stop this sooting? Its got to be loss of pressure, I tried to give it more neck tension, but it did not help. I am wondering if hotter primers would help? I am using the CCI BR2 primers.

thanks again, Ron Tilley
 
Ron,

If they're non VLDs, try jumping them more.

I shoot 210 Bergers loaded to 3.15" in a .308 Winchester case & 200 SMKs. The throat is way too long to get the SMKs anywhere near the lands, but they shoot fine at 1200 yards jumping 100 thousandths & more. Admittedy, I'm molying, but both projectiles seem to settle to better ES &SD figures when they get a run up to the lands.

John
 
I had that happen to me as well. I have a 300wsm reamer throated for berger 210`s and cut for norma brass. During barrel break in/fireforming all I had on hand was 168`s. When I seated them waaay out, my cases were very dirty. I dont have any figures but hardly any bearing surface was in the neck with the 168`s and still didnt touch rifling. Went to a longer bullet and it stopped. I`m suprised the non vld has a shorter bearing than the vld. Usually it`s the other way around(??) chris
 
+1 on John's comment. Back them out even further, until you have a good solid neck hold on the bullets.

I took a clinic from Jim Owens back a few years ago in Houston, and he had us start with our favorite load and load touching the lands, then back out by 0.005 until we were about 0.5 inches out from teh lands. It was amazing to see, but there were accuracy nodes dependent on the seating depth just like you find in velocity. If you keep backing up you'll find one of those remote accurate launching pads.

JeffVN
 
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