doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com .30-30 barrel lining?

Should Mr. Polecat even consider sending a .311-312" diameter bullet down a presumably .308" bore in a rifle barrel that has thin walls and already has a ringed chamber? I realize the increased pressure probably wouldn't mean much in a stout bolt action with a thicker barrel in good condition, but this sounds questionable. Or are you suggesting that he also have the barrel rebored and rifled to the next larger bore size? I'd imagine this would be very difficult (and costly) to do with a drilling.

I'd maybe be looking at some smaller .308" diameter chamber insert for a smaller low pressure cartridge, even if it required some wild-cat creativity to form brass and reload. Of course, this likely won't be satisfactory if the goal is to use it for deer hunting. And it might involve having an exceedingly long throat which wouldn't do much for accuracy. Sometimes, it just makes more economic sense to simply retire a gun and either sell it as is, hang it above the fireplace, or part it out.

"IF" he could find the right person tp do it the bores could be "Freshed" to take .311"-.312"m bullets ala muzzle loader style & not have to be Bored. This of course assuming that enlarging the neck by only that amount would clean it up.
I do not know who might could do this work or what it might cost though.

Not that many of those Hollenbeck drillings around, shame to lose it if can at all be saved

As close as .311 and .308 are, the bore might just be a matter of deepening the grooves a bit. .321 might be a bit much for that, though, I dunno. People used to shoot .311 bullets through the old .308 bore Mini-30 all the time, and nothing blew up. Just wasn't as accurate as it ought to have been, I reckon.

My biggest concern is the chamber, though. I don't know what can be done about that other than:

1. rechamber to .30-40 Krag, which probably ought not happen because of the thin chamber.

2. reline the barrel and recut the chamber, which may not be able to happen (at least in .30 caliber) due to the thinness of the barrel. .25-30 or .25-20 might be an option there, though. I'd sure hate to go below .30 though...

I guess there isn't some way to fill the bad spot with some kind of super-special epoxy goo (or weld, though I can't see how that could be done) and then recut the chamber, eh?

Regardless, then there is also the issue of finding a gunsmith that can be trusted to do the work properly. If this gets screwed up, I can't just buy another one. I am not sure I have enough faith in any of the guys I know of around here to do any of this.

I have shot thousands of .311 cast bullets through a .308 bore, no issues.

As far as an eroded chamber, that is a tough nut.

I would say leave the gun as is, and if you need to fire the gun, use a steel chamber insert to fire a hand loaded low pressure 32 H&R Mag round.

Mike

fun reading
https://www.chuckhawks.com/rifle_chamber_insert.htm

Firing a .311 bullet through a .308 barrel won't hurt anything, as long as the chamber neck diameter is large enough to expand and release the bullet easily. It will be moving when it encounters the rifling and at the low end of the pressure curve. Once it has traveled the length of the bullet's shank in the .308 barrel, the bullet will be .308 also. Of course this assumes a "cup and core" bullet; monolithic bullets sometimes cause pressure spikes in barrels with groove diameter the same as bullet diameter, if there are no relief grooves.
Mike

Would a 30-30 Ackley improved reamer clean up the pitted shoulder area ?

Probably not, but it might be worth a chamber cast to find out. Assuming you can get the casting out past any 'lock ' caused by the errosion.

Another expensive option would be to developer a 30-30 extra long, have a reamer ground that arries the case shoulder forward the requisite amount, and have custom dies made.

There is 30-30 basic brass available that is over 3 inches in length and you just need a .005 or so ?

Could a 30-30 reamer be run a little deeper in the chamber and accomplish the same ?

Unfortunately the bad spot is right at the bottom of the shoulder. I think the only way to be rid of it is to ream to something that is larger in diameter. I don't think .30-30 AI would get it there.

OK, more info, the bad spot is in the NECK, Shoulder, bottom of the shoulder, ??
Mike

So far we have
severe throat erosion and an oversized neck,
The chamber has a ring of erosion/pitting in it.
The ring is way down at the bottom of the shoulder, unfortunately

Yep, this.

Postoak already mentioned the 30-30 A/I,,,,
I believe a rechambering to 30-30 Ackley Improved (30-30 AI) would solve the most severe problem you have of the erosion ring at the bottom of the case shoulder in the chamber.
That's not allowing you to even fire the rifle bbl w/o pounding out the empties from the muzzle.

Here's a link to another unrelated forum and discussion but there is a side by side pic of the standard 30-30 and the 30-30 A/I chamber dimensions. Scroll down the page on the link.

Quite helpful I think in figuring out if the latter would clean up the problem existing in the chamber now..
https://www.24hourcampfire.com/ubbthread...nd_cast_bullets

The 30-30 AI expands the case body diameter behind the shoulder and moves the shoulder forward (resulting in a shorter neck).
That larger dia case body reaching farther forward may remove that erosion ring causeing the extraction problem.

It'd still chamber and fire standard 30-30WCF. The cases would just fireform to A/I cases.
Minimum material removed from the bbl, no rebore, relineing, ect.

Keep loads (very) reasonable and I think the gun will never know the difference and could be usefull once again.

As for the throat erosion,,perhaps it isn't as big a deal to shooting quality as you might think. Try it w/o any changes. Then if you think cleaning it up a tiny amt by extending the throat and loading the bullets out further will help,,it's a simple hand reamer job.

Chamber reamer rental is quite reasonable these days from a few sources. The 30-30 A/I is generally a common stocked item.
..as are 30cal throating reamers.

,,,,,
The only other thing I can come up with is to run a 303British reamer into the chamber and push the shoulder forward. That'll recut the neck slightly larger than it is right now of course. But you seem to have 'an oversize neck' problem too..
Run the reamer on a .308 pilot of course.

Only deepen with the 303Brit chambering reamer to the depth that the taper of the body of the 303 reamer meets and matches the base dia of the 30-30 chamber (.422d).
The shoulder of the 303Brit chamber and the shoulder of the 30-30WCF chamber are the same at .401d.
Even the shoulder angle is within 1/2 degree.
So perhaps the 303reamer being tapered more than the 30-30 as it cuts deeper, pushing the shoulder forward AND will clean up that erosion ring problem.

You will of course end up with a wildcat sort of a short 303Brit w/a 30-30 case head size.
Depending on how deep this crazy idea allows you to go before the 303 reamer starts to cut away the 30-30 chamber base,,perhaps you can still use 30-30 brass,,or maybe 38-55 brass (a little longer I think.
Size in a 303Brit die and load. Don't use an expander,,just size the brass and 308 bullets will seat just fine.
Or .311 lead down a .308 bore won't hurt with light loads.
This should cut a nice new clean throat in the bbl for you too.
All 3 problems taken care of..!

....if it works of course..Just a goofy idea that's all.