Which dies for 7.62x39?

[ballman6711]

I recently started shooting my AR chambered in 7.62x39 again. I found some factory Bellom 123gr fmj ammo that it really likes. I pulled one of the rounds and measured the bullet diameter at .310.

So I found a set of RCBS dies, but they came with a .308 and .311 expander ball. Since the rifle shoots the .310 bullets so well, I would like to stick with those, but could go to a .311 if that's my only option.

I see a few dies on the market that will let me expand to .310. I did buy the above mentioned RCBS dies and probably could polish the expander ball down a bit, but would rather not, since I may want the option of loading .311 for my SKS or AK at some point in the future.

One die I've found is the RCBS neck sizing die. I can get different size expanders for that, but that would have me full length sizing and then neck sizing afterwards, adding an additional step. I've also found the Lee fl sizing die which comes with a .310 expander, but I'm not sure about the quality based on reviews I've read.

Any suggestions are welcome on these two dies OR any other dies that would work. Thanks!

chris

 

[Bcwitt]

Take the decapping rod & chuck it in a drill. Hold some krokus cloth on the 311 till you reach your perfured 310.

 

[ballman6711]

Take the decapping rod & chuck it in a drill. Hold some krokus cloth on the 311 till you reach your perfured 310.

This is probably going to be the route I take, I can always buy another expander later.

chris

 

[Bfh_auto]

This is probably going to be the route I take, I can always buy another expander later.

chris

That's the best route. The extra neck tension on a larger jacketed bullet won't show up in accuracy in most AK,SKS, or AR platforms.

 

[jimboecv]

.311, try that first, as is and see what you think.

 

[lightman]

I believe I would try loading with the 308 expander and see how well it works. Expanders are not real costly so you could buy another size if the 308 doesn't work to suit you.

 

[mdi]

Is the .308 expander .308"? Is the .311 expander .311"? Depends on what ID the expander produces in the case mouth and how much neck tension is needed/wanted. IIRC, a .002" to .004" interference fit is normal. I think I would start with the .308" expander and try that. Chamfering the case mouth and/or lightly flaring will help seating. I flare all my handload case mouths, makes starting flat based bullets much easier and flare is removed with a deflaring die (aka taper crimp die).

Will your groups improve, your handloads shoot better with .002" more neck tension? The difference between a .308" bullet and a .310" billet is .001" rifling engagement...

 

[Bcwitt]

I found that to be nessesary when pulling down 762x39 for use in 303British. The thin Brit brass just wont hold a 310 bullet w a 311 button, & the 308 button was too tight. Made seating bullets concentric very difficult. 310 was just right.

 

[jimboecv]

My Ruger American in x39 likes .308s, go figure.

 

[Bcwitt]

My Ruger American in x39 likes .308s, go figure.

Just goes to show, every gun is different.

 

[ballman6711]

Is the .308 expander .308"? Is the .311 expander .311"?

Yes, I measured both and they are .308 and .311. I also made a few dummy rounds using the .311 expander and chambered them. Three chamberings left me with about .002 ~ .0025 setback, unacceptable to me.

I ordered a .310 expander/decapper and a few bullets, so I'll have to make another couple dummy rounds when they get here.

chris

 

[Lennyjoe]

My AR like .311 bullets. I shoot the Hornady 123 gr FMJ and JSP out of it with Reloader 7.