Sticky bolt with only 43gr Varget (308 SMK 175 in Norma brass)

[zhangla]

Hi,

I am running into some strange problems while I started switching from IMR 4064 to Varget with my 308 handloads.

I have been using the same bunch of brass and bullets. With 4064, I have been doing 43gr smoothly. No sticky bolt while chambering/unchambering live/fired rounds.

However, with Varget, I started having issues lifting the bolt (not extracting brass) after the rounds are fired with merely 43gr of powder. It is supposed to be the classic sign of over pressure, but the primers look good to me (see image), and it is only 43gr. More interestingly, when I go up to 44.5gr of Varget, the stiffness of bolt lifting did not change. 2 other interesting observations:

1. The live rounds with Varget are smooth to chamber or unchamber
2. It's very hard to close the bolt when I put the fired brass with Varget in the chamber

Has anyone seen this issue before?

 

[bas402]

Yep, Having the same problem with Norma brass in my 6.5 SAUM. I have reduced my load from 60gr to 56gr of H1000 and the SAME stiff bolt issue. My primers look great,no ejector marks or other pressure signs except even at such a VERY mild load I can no rechamber a fired case. The brass is super soft at the case web, so soft it will not spring back, thus making it VERY difficult to raise the bolt but when it does you can extract the case out of the chamber with your little finger.

 

[zhangla]

It could be the Norma bass, but I had no sticky bolt issues when I load 43gr of IMR 4064 into the same brass. Strange.

 

[Bill Larson]

Any norma brass i`ve ever shot was dissapointing.... Too soft.... Go to lapua.... 2nd best winchestr.....

 

[InfScout1/69]

Maybe head spacing issue? Not setting the headspace back far enough can do that.

 

[zhangla]

I originally suspected headspace issue, but the live rounds before firing can chamber and unchamber smoothly. It is only sticky after the rounds have been fired.

 

[bas402]

Have you taken it down 2gr? I had the issue going up or down 2gr

 

[bas402]

Maybe head spacing issue? Not setting the headspace back far enough can do that.

If he can chamber a resized round easliy it's not HS.

 

[zhangla]

If I go down 2 grains, it will be only 41gr of Varget...

 

[InfScout1/69]

?? If he's set his shoulders back just enough to chamber and no room for expansion.. Bolt will get sticky

 

[bas402]

If I go down 2 grains, it will be only 41gr of Varget...

I know, drop it 1gr and I bet you will still have stiff bolt lift

 

[SWRichmond]

I am running Norma brass way over loaded with much more Varget than you behind a Berger 185 Jugg. No extraction or bolt lift issues at all. I wouldn't call Norma brass soft. It's wearing like a board for me, and I just bought some more. Is your chamber rough? Factory barrel? I have had this issue with factory barrels. Also, your fired cases have some arc-shaped scratches on the heads which make me think something is going on. See 'em?

 

[zhangla]

Yes, after being fired these brass headstamp show signs of friction with something (I suspect it is the bolt face). It can be caused by headspace issue, though if I chamber and unchamber live rounds these signs of friction do not show. I am guessing these friction signs were printed on the headstamp when I lift the bolt after firing.

 

[bas402]

Question, have you been using this same Norma brass with 4064? If so how many cycles?

 

[zhangla]

Yes I have been using the same brass with 4064 before, about 3-4 cycles so far. These brass were not new brass but from my once fired Norma Match 168 SMK retail boxes.

 

[InfScout1/69]

I'm telling you... Bump your shoulders another .001 or .002 and your problem will go away.

 

[InfScout1/69]

Also with that many firing it's time to anneal your brass 8)

 

[InfScout1/69]

And out of those firing are you just neck sizing or FL sizing?

 

[bas402]

Yes I have been using the same brass with 4064 before, about 3-4 cycles so far. These brass were not new brass but from my once fired Norma Match 168 SMK retail boxes.

You can do what you want but on my NEW lot of 7SAUM Norma brass I did not notice any issues with bolt lift on my first firing, it came after I F/L sized and. Bumped back .0015" in which they chambered like virgin. It started during the second cycle (very slight on a couple) then I noticed fired cases wouldn't chamber. Reduced charge wts no help,bumped back to .002",.0025and even .003 just as an experiment but I still had it. Finally went to remmy brass...problem was gone. My smith measured my webs and even with chamber pressures of 53k the webs were expanding .0015". Like I said do what you want it's just what my problem was and yours sound very similar