Monday, September 08, 2014

I think I froze some brains at Brownell's

I was browsing through their site and noticed one of the 'Ask one of our techs!' things, and "Shazam!" thought I, "I shall ask these experts about my idea for a AR-10 in .30-30!"  So I did: "What AR-10 bolt could be modified to work with the .30-30 casehead?"

Three days later: "You need to talk to a qualified gunsmith, nothing we can recommend."

Well, crap.  So I guess I start going down a list of "What can you get a AR-10 bolt in, and what's the largest/closest size head?"


Glen Filthie said...

Not trying to be a dink or a snark, Firehand...but my question to that is...why?

The gun wanks around here proclaime the .30-30 is ballistically similar to the 7.62x39...

Dammit, my brain just vapour locked too!!! :)

If you do go forward post a range report, will ya?

Sigivald said...

.300WSM looks like maybe the biggest, and is at least larger than .30-30, a bit.

Don't know how you're going to feed .30-30 out of the magazines, though, with those rims; there's a reason all the serious mag-fed designs are rimless.

(For that matter, custom mags might be needed, and ... that's just no fun.)

Firehand said...

"Why? Because I can!"
Besides the general "You're firing WHAT in that?", here's my thoughts:
Ammo available anywhere.
With handloading can use pointed bullets anywhere from 110 to 170 grains.
With Leverevolution powder and bullets, that's a 160-grain bullet at equal velocity to 7.62x39.

On the magazines, I'm thinking do it the way the Romanian PSL does: about 1/3 up from the back of the lips there's a cutout in each; you push the rimmed base down there and then back; that way each cartridge rim is in front of the one below. Works for them, should work for this.

denis miller said...

Is someone even suggesting that the .303 Lee-Enfield, rimmed cartridge, is not a serious weapon?

Firehand said...

Now there would be one! Set up a PSL or AR10 for .303!

AM said...

It is a totally doable project. Both rounds have a 51 mm case length, and the same rim diameter. You can fire a 30-30 from a 308 Win Chamber, but the body will often split in the fire forming process.

The problem will come from loading rimmed cartridges from a magazine. Not a problem if you single load with a single load follower.

But, I'm pretty sure that a custom 5 round magazine would be doable.

Daniel Watters said...

AM: The rim diameter is not the same. The .30-30 rim runs closer to 0.506", versus ~0.473" for the .308 Win. The only member of the .30-30 case family that has a ~0.473" rim is the .225 Winchester.

For those who mentioned the .303 British, it would likely be too long for the AR-10 magazine, but the rim should be close enough to use the same bolt as the .300 WSM/.300 RSUM variants.

I seem to remember reading about a European AR-type manufacturer that was building rifles in 6.5x55mm Swede and 7.5x55mm Swiss. You have folks here in the US offering .30-06, .300 Win Mag, and .338 Lapua AR variants.

Daniel Watters said...

The manufacturer of the AR-types in 6.5x55mm and 7.5x55mm was Luvo Prague.

Sigivald said...

Is someone even suggesting that the .303 Lee-Enfield, rimmed cartridge, is not a serious weapon?

It's not a serious design in the modern sense, no.

It's seriously powerful, and a top-ranked weapon of its era.

(Likewise the Mosin-Nagant, also using a rimmed cartridge.

Which, note, everyone abandoned the second people stopped loading from strippers and using replaceable magazines.

There are reasons for this.)

AM said...

The rim diameter is the same enough that an M98 chambered in 308 Win can load a 30-30 and fire it. The guy did that three times, and only on the third time did a case split.

The other two were fire formed to say the least.

I think Mike McCabe still has the pictures, it was one of his clients that did that.

Daniel Watters said...

AM: That particular Mauser might have had a generous bolt face. I wouldn't guarantee that experiment would work with a different example.

Come to think of it, it probably didn't hurt that the M98 bolt face has an open bell-shaped cut to allow the cartridge rim to funnel up under the extractor hook during feeding. The narrow-body of the .30-30 case in the .308 chamber likely gave it enough wiggle room for the wider rim to sit off-center on the breechface. An AR-10 or Remington 700 bolt isn't going to give you that possibility.

AM said...

Yeah, the recessed bolt face is more problematic, but it is only about a fifteen thousandths cut on the lathe to add the wiggle room to a recessed bolt face.

Daniel Watters said...

You'll likely need to relieve the extractor hook as well, given that the .30-30's rim is slightly thicker.