Need help with 6.5x47 Lapua

[bender338]

I recently received my Defiance 6.5x47 rifle and running into some pressure issues.

Barrel is Bartlein 1:8 twist

Today I tried to shoot some factory Lapua 123 rounds as well as some of my reloads. After couple of rounds, I experienced hard lifting bolt. What could cause that?

Here is the load that I was shooting.

123 Scenar - 39.8 H4350 loaded 20 thousands of the lands (measured from ogive)
139 Scenar - 39.6 H4350 loaded 20 thousands of the lands (measured from ogive)

Accuracy was really good (see picture). What should I do next? Should I clean the rifle and try again?

I am shooting it with Surefire suppressor, and thinking that the can makes the barrel dirty fast, thus creating higher pressures. Rifle has total of 30 rounds through it.

Any help is really appreciated!

This is the 123 Scenar MY RELOAD with 39.8 H4350.

 

[DennisH]

36.2 grains of Varget works perfect with the 123 Scenars in my rifle. You might be a little on the hot side.

But I just noticed I was running 41.2 grains, H4350, with 130 Bergers with no issues!

Have you double checked your headspace adjustment?

 

[X-Caveman]

That seems pretty mild. Was it virgin brass & did you have sticky bolt with the factory stuff? If the brass was fired in another barrel, it could just be a difference in the chambers. I have three 6.5x47 barrels, and unfortunately, brass is not interchangeable. I shoot 6.5x47 suppressed with 40.0-41.0gr H4350 with Berger 130s and 140s and don't get pressure. Mine are 4 groove Krieger, Brux and Hawk Hill. .294" no turn neck, .123" freebore.

 

[bender338]

Thank you for your response brass is brand new and I was firing Lapua factory ammo. I cleaned the chamber and it was dirty. No idea how it got dirty, maybe from suppressor. Maybe dirty chamber is the cause of over pressure.

Hard bolt lift was on both factory and reloads.

 

[RJ338]

Get a Cerrosafe cast done of your chamber and check the neck diameter of your chamber.
Sounds like you don't have enough clearance. Does a bullet slide into a fired case? If not,
that is probably your problem.

 

[TikkaSporter]

Having similar issues with a new Deviance Deviant action and Bartlein barrel in a 260 Remington...

Is your bolt lift all the way up, or just at the last part of the lift (bolt clicking)? I'm getting the 'bolt click' with lighter than expected loads, and no other pressure signs. A few things to check:

- Neck clearance, slip bullet into fired neck test or measure fired neck vs loaded round neck, should be about 0.003" or more difference
- Headspace issue
- Lube cocking mechanism and lugs on bolt
- Not likely in your situation, but neck donuts and the dreaded carbon ring can cause pressure, I've seen it first hand on other rifles.
- And most likely if you have bolt lift only at the top of the bolt stroke, is a chamber that is too tight towards the back (worn, dull reamer, rough chamber, or out of spec brass). I could take a fired piece of brass, polish it, put it back in the chamber, close the bolt, and see 'scuff marks' on the back 1/3 of the case.

I'm sending mine back to the smith to look it over and polish the back of the chamber if needed...

 

[turbo54]

Sounds like neck clearance to me, also.

Measure the neck of a couple loaded rounds - I'm guessing you'll get .289" or .290. Next, measure neck diameter of a fired case. It needs to be at least .0025" bigger than the loaded one. .003 or .004" is better.

If you don't have at least a .0025" difference, you'll need to neckturn your brass.

 

[DennisH]

If you don't have at least a .0025" difference, you'll need to neckturn your brass.

Neck Turning is simple. I would go that route if it was mine. .0005, just skimming the neck might do the trick.

 

[kev77]

4-5 thou neck clearance is the best for the 6.5x47 " we all run closer to 5tho clearance