Sticky Bolt

[223ai]

All -

I received my new rifle last week, and started some load development for it right away. My rifle specs are as follows:

FN SPR action, trued
Bushed firing pin hole
Brux, 10 twist finished at 20 inches and threaded
.308 match chamber
CDI bottom metal
Mickey A3 pillar bedded
USO ST-10 in TPS rings

I have 1000 pieces of 7.62 WCC Nato brass that was fired out of a match bolt gun, A bunch of Ramshot TAC, and a bunch of 155 Scenars. I ran the brass through a FL sizing die, trimmed on my giraud to 2.008, and loaded the 155's to 2.800 COAL. I started with 42.0 grains of tac, and worked my way up to 44.0 grains. I used cci 200's for the primers.

While accuracy was nothing to write home about with any load, what surprised me the most was that I had a sticky bolt from 42.0, all the way to 44.0. No other signs of excess pressure were evident.

We did shoot some factory black hills and did not have the same sticky bolt issue.

I have virgin winchester brass being delivered today, and will restart this process with varget and virgin brass.

any insight into the sticky bolt?

 

[Victor N TN]

Re: Sticky Bolt

If you have the right tools to do so, measure from the case head to the shoulder on a couple of cases both fired in your rifle and after being full length sized. It should be around .002" If your cases are in this range, try running them through a "small base" sizing die every now and then.

Just to cover bases. Is your new rifle lubed on the bolt lugs?

 

[223ai]

Re: Sticky Bolt

I have an RCBS precision micrometer that I measured the brass with. The brass came to me as once fired and read right at 0 on the mic gauge. I bumped the shoulder .002, and measured after I fired, and all brass is showing back at 0. Not sure if this is what you are referring to?

The rifle is definitely lubed properly.

Thanks for the feedback.

 

[19Scout77]

Re: Sticky Bolt

I have some TAC but haven't used it yet. Before switching to the new brass, use some of the "sticky" brass with Varget first. Only screw with one variable at a time.

 

[223ai]

Re: Sticky Bolt

I have not been impressed with TAC, except that it meters great. I'll load up some of the 7.62 brass with varget alongside the Winchester brass...