Setting .311 bullets in .308 sized necks? Bad idea?

MosinMan13

MosinMan13

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I’m relatively new to loading, and I’ve not yet loaded for my 7.62x54r ammo yet, I’ve picked up a Lee for set out of availability, however I’ve quickly learned Lee makes some odd assumptions about 7.62x54r.

I slugged my bore at about .312 depending where I read off of, so I’ve picked up some Sierra .311 180gr soft point spitzer bullets and H4350 powder, All my research tells me this is one of the better routes for what I’m after.

My problem is I’ve realized Lee gives you an expander for .308 out of the box, a little frustrating, I have the expander for .311 on order though given the Covid I’m looking at late July before I get it.

I did a test bullet with no primer or powder and pressed the .311 bullet into the .308 neck, no problems, though noticeably tight, and if I didn’t know better, the neck at the shoulder bumps out and you can visually see the outline of the bullet where it stops, I could just be self conscious.

Is this unsafe? I’m positive this is a stupid question when it comes to reloading, I’m just wondering if that tightness is going to stack too much pressure, and if that possibly disfigured neck might be a point of failure?
 
I am a simple person but for .308 I would use bullets intended for .308, regardless how anything measures. Esp when its DIY measurements
 
Teac said:
I am a simple person but for .308 I would use bullets intended for .308, regardless how anything measures. Esp when its DIY measurements
Click to expand...

I’m with you there, but it’s a nearly 100 year old Milsurp, the bore is well worn and slugs just a thousandth shy of .312 so by the book .311 makes sense. I’m more concerned about the case resizing and if the neck ought to be sized by the book or if allowing the pressing of the .311 bullet to fit is something to be concerned about.
 
.004 of neck tension is perfectly fine. Perhaps some F class reloaders wouldn't make it common practice but for a Mosin you'll be fine. It'll work your brass a bit harder that's all.

If it's good brass you can anneal it to get way more reloads out of it. I have Lapua brass for a Mosin Sporter that shoots almost 1/2 MOA at 200M that I anneal after every 2nd reload or if I feel the bullet tension is starting to vary between cases as I load them.

For PPU or S&B brass and non match bullets shooting irons on mosins, I wouldn't care about .004 neck tension myself.
 
OP, you're overthinking this issue.

M13, why do you assume the bore of the OPs rifle is worn? I have both M91 and M91/30 rifles with pristine bores, that slug .3085 to .313.

OP, If your bullets have a flat base, you may see a bit of shaving when you seat them.

.003 isn't much to get worried about in this case.

All that will happen is that you will have very slightly increased neck tension. Nothing to worry about IMHO.

If push comes to shove, just flare the case mouth very slightly, so the bullet base will enter without being shaved.

The other option is to use your case deburring tool to cut an angle on the inside edge of case mouth.

MuthaFunk explains it well
 
bearhunter said:
OP, you're overthinking this issue.

M13, why do you assume the bore of the OPs rifle is worn? I have both M91 and M91/30 rifles with pristine bores, that slug .3085 to .313.

OP, If your bullets have a flat base, you may see a bit of shaving when you seat them.

.003 isn't much to get worried about in this case.

All that will happen is that you will have very slightly increased neck tension. Nothing to worry about IMHO.

If push comes to shove, just flare the case mouth very slightly, so the bullet base will enter without being shaved.

The other option is to use your case deburring tool to cut an angle on the inside edge of case mouth.

MuthaFunk explains it well
Click to expand...

Well thank you and MuthaFunk for your thoughts on that, more or less that’s what I was looking to find out is just experience, I measured the neck with my calliper to see if I was just seeing things and I am, there’s no distortion in the brass at all so I'm going to give it a go tomorrow, 50gr of H4350 starting charge, we’ll see how she goes.
 
I’ve been using lee dies for a while for 7.62x54r and noticed that the .311 bullets seat a bit tight. Never realized that the expander is a .308
I’ve gotten 5 or 6 loadings so far on some PPU brass and the brass is still good I haven’t noticed any damage on the necks so I’m thinking it shouldn’t be anything to worry about
 
Deathrawt said:
I’ve been using lee dies for a while for 7.62x54r and noticed that the .311 bullets seat a bit tight. Never realized that the expander is a .308
I’ve gotten 5 or 6 loadings so far on some PPU brass and the brass is still good I haven’t noticed any damage on the necks so I’m thinking it shouldn’t be anything to worry about
Click to expand...

Have you been annealing it yet?
 
Simple fix, lube the inside of the necks with powdered graphite to ease the seating friction.

CH3epH9.jpg


Below I use the Lyman type "M" expander on my cases for my AR15 rifles to increase bullet grip. And this expander is .003 smaller than bullet diameter.

ohIUcpd.png
 
Mosins are supposed to be .311-.312 range they aren’t a true .308. Weird lee gives you the .308 expander, I had a similar issue with carcano bullets so bought the Lee universal expander, works like a charm
 
Bubba Yugga said:
Are you saying that the increased neck tension helps ignite the ball powder?
Could this be a workaround to not using magnum primers?
Click to expand...

Here is a receipe for poor ignition, misfires and poor accuracy.

Load a light bullet. In 308, 303 and 8mm, anything 150 gr or less is "light".

Load a ball powder that only fills 3/4 of the case, or less.

Light neck tension and no crimp.

Standard primer.


I once loaded a 1000 rounds of ammo like that for plinking purposes - and found it almost useless. I was not inclined to pull the bullets and start over, so I tried applying a firm crimp. That change made the ammo usable.

The next time I loaded the 1000 rounds of plinker, I used high neck tension (sized it 308 with no expander ball), used a magnum primer and crimp. Perfect ammo.
 
Ganderite said:
Here is a receipe for poor ignition, misfires and poor accuracy.

Load a light bullet. In 308, 303 and 8mm, anything 150 gr or less is "light".

Load a ball powder that only fills 3/4 of the case, or less.

Light neck tension and no crimp.

Standard primer.


I once loaded a 1000 rounds of ammo like that for plinking purposes - and found it almost useless. I was not inclined to pull the bullets and start over, so I tried applying a firm crimp. That change made the ammo usable.

The next time I loaded the 1000 rounds of plinker, I used high neck tension (sized it 308 with no expander ball), used a magnum primer and crimp. Perfect ammo.
Click to expand...



Ganderite, you are so knowledgeable, that you often assume people understand why the fixes you describe work. No diss intended.

When neck tension is increased, by different methods, parameters of ignition change, not always for the better.

Using a good magnum primer will increase the positive efficiency to ignition
 
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