Do I need to turn my necks on my 6.5 x 47

[Never Forget]

I received my 6.5 x 47 Lapua yesterday and plan on breaking it in tomorrow. My reamer print says the neck should be cut .2933 at the neck shoulder junction and .2922 out at the end of the neck. My loaded rounds measure from .2912 largest to .2905 smallest. The vast majority measure right at .291. This was measured with a Starret mic not a calipers.

My plan was to not turn the necks, I've had fantastic results with both my 6BR's with no turn necks but those loaded rounds measure .002 clear of what that reamer prints has listed. Am I asking for pressure issues only having .001 clear?

The loaded rounds do chamber without any issue's.

Thanks, John

 

[22DASHER]

Yes neck turn them

 

[noload]

I would go for .003" min. clearance .

 

[Never Forget]

I should add this is a benchrest gun.

 

[TerryPohl]

You need a little more clearance there.
Terry Pohl

 

[geraldgee]

Minimally you should be safe enough pressure-wise with a clean chamber. But after that it's anyone's guess. And who is to say the next lot of brass won't be fractionally thicker? If you don't want to turn necks yourself, consider sending your brass off to have it turned. It certainly won't do any harm and will undoubtably help with concentricity.

Enjoy you 6.5L - I have one set up for hunting. I am very pleased with it.

Gerald

 

[dskogman]

Prints and actual are 2 different things. If it chambers I'd fire a few and see what the fired size is.

 

[hogpatrol]

Prints and actual are 2 different things. If it chambers I'd fire a few and see what the fired size is.

This ^^^^

 

[spclark]

This ^^^^

Agree.

Take a couple new bullets with you. Fire a round in your new rifle, then see whether one of those bullets will slip back into that fired case's neck.

If it does, and flops around or you can drop it freely into that case, you're fine; your neck has 'generous' clearance.

If it does, and it just fits with little to no force applied by your fingers, you're fine too but your clearance is minimal. As necks can thicken over time from firing you may want to consider a light skim cut to even them up front to back to avoid issues later.

Does that case chamber easily again after being fired or does the bolt resist being locked when you try? If a bullet won't fit in that neck, your chamber may be too tight.

Remember you only need turn case necks once for their lifetime.

 

[Pappy42]

My 6.5x47 likes a case neck, with seated bullet, of 2 to 3 thousandths under chamber neck diameter. YMMV

 

[Never Forget]

Prints and actual are 2 different things. If it chambers I'd fire a few and see what the fired size is.

Well I did the break in and had no issues chambering. It has a Surgeon action and really puts a lot of side pressure on the case during extraction which deformed it out of round quite a bit. I managed to very slowly extract 1 case and got my finger in there to relieve some of the extraction pressure and it stayed round, it mic'd right at .292, my loaded round was .291.

I did try re-chambering a round after it was fired, it seats all the way but the bolt wont close. It would with a little force but I'm not doing that.

To be safe I'm going to give them a skin cut, I noticed after firing and resizing some cases now seem to be out .001, they were out .0005 straight from Lapua. They were sized with Whidden dies.

I'll do some research before posting a ton of questions here on the turning process. I think I have most of it figured out already, going to purchase K&M equipment.

Thanks for all opinions and advice, John

 

[hogpatrol]

Well I did the break in and had no issues chambering. It has a Surgeon action and really puts a lot of side pressure on the case during extraction which deformed it out of round quite a bit. I managed to very slowly extract 1 case and got my finger in there to relieve some of the extraction pressure and it stayed round, it mic'd right at .292, my loaded round was .291.

I did try re-chambering a round after it was fired, it seats all the way but the bolt wont close. It would with a little force but I'm not doing that.

To be safe I'm going to give them a skin cut, I noticed after firing and resizing some cases now seem to be out .001, they were out .0005 straight from Lapua. They were sized with Whidden dies.

I'll do some research before posting a ton of questions here on the turning process. I think I have most of it figured out already, going to purchase K&M equipment.

Thanks for all opinions and advice, John

Also, check your case length after firing. After the first time they may need trimmed.

 

[Never Forget]

Also, check your case length after firing. After the first time they may need trimmed.

I did check that, the shoulder blew forward .010 but the trim length remained the same or shrunk .001, thought that was a little strange. I bumped the shoulder back .002 and it chambered easily.

 

[spclark]

0.010" is a little much for first firing with new brass, even using Lapua.

The COAL shrinkage you mention wouldn't at all be unusual with that much brass getting re-shaped, and remember the cases sides are moving outward too.

As for that shoulder movement: are you able to converse with whomever it was you chose to fit & chamber your barrel as to whether they used go/no go gages during the work? With new cases that short out of the box (Lapua Palma cases I use routinely run no more than 0.003"-0.004" shorter than the three Palma chambers I'm using presently and I do get an infrequent misfire with new-brass loads in one rifle) I'm surprised you're not mentioning misfires due to light primer strikes.

 

[Never Forget]

0.010" is a little much for first firing with new brass, even using Lapua.

The COAL shrinkage you mention wouldn't at all be unusual with that much brass getting re-shaped, and remember the cases sides are moving outward too.

As for that shoulder movement: are you able to converse with whomever it was you chose to fit & chamber your barrel as to whether they used go/no go gages during the work? With new cases that short out of the box (Lapua Palma cases I use routinely run no more than 0.003"-0.004" shorter than the three Palma chambers I'm using presently and I do get an infrequent misfire with new-brass loads in one rifle) I'm surprised you're not mentioning misfires due to light primer strikes.

I've only fired 40 rounds so far but haven't experienced anything negative. I was surprised by how much the shoulder blew forward, I triple checked a bunch of the unfired brass I have and they all measured the same, all 40 rounds blew forward, about .0085 on the light loads and 10 on the rest. I have the go/nogo gages as I purchased them with the reamer and all seems right to me when I check. I'll see my smith later this week and ask his opinion.