barrel unwrapping

[ssgross]

Santa delivered a bit late, but better late than never. There aren't too many USGI-still-in-the-wrap barrels left. I look regularly, and have seen 2 in the last last couple years, including this one. Used to find 1903a3's in the wrap regularly popping up online - but haven't seen a single one since the one I found for a project before the pandemic.

Anyhow, the unwrapping is always fun - and if you're not careful and put some thought into it...very VERY messy. So I thought since this is likely the last one, and it's a bit rare too, I would do a post.

No bow or ribbon?


Peel back and cut off the wrapper, except for where the vice is holding it. don't want a mess there. Nasty.


Use a piece of wood like a paint stir to scrape off as much as you can, then do the same with a blue shop paper towel. Once we clean one end, we will rotate and remove the wrapper on the other side to avoid a mess. Now here is the key...Kerosene. Hold a shop towel under the barrel and liberally squirt on the kerosene. In all my experience, nothing else works as well. Not mineral spirits, not hot soapy water, not hoppes #9, not lacquer thinner nor acetone and not even brake cleaner can touch kerosene when it comes to this thick, hard, waxy cosmoline. Also has the advantage of being the world's best water displacing oil.

It took me only 2 shop towels to get to here. Once the bulk is removed, use a brush and more kerosene to get in all the tough spots.

here is what was underneath all that....A Marlin contract barrel! Here are all the markings I could find. No date, so I think this means it was the 1952 marlin contract as opposed to the earlier one where the barrels were dated and blued.


Curios mark behind the lower band. Looks to me like a simple forging blemish that was too pronounced to be removed when turning.


The finish is bone dry after cleaning with kerosene. Use plain motor oil (no detergents or solvents) for the first oiling. After wiping off the excess, I like to rub in plenty of RIG grease as my eternal rust preventative before a final wiping down.

Let's clean the bore. Kerosene on the patch with a standard jig will push it all out.

I actually took a video pushing this out. It was quite satisfying. Is it possible to upload without using youtube or other service? I don't think so. Here is an attempt with Vimeo.
I don't see a video, even though I see the link in the post editor, here is the link. https://vimeo.com/1045888614
Cosmoline pretzel while you watch?

It's old and hard enough to stay very intact. You can feel a small amount of resistance trying to pull it apart.

After pushing out all the grease. Squirt in more kerosene and switch to a Dewey style jag and scrub-a-dub-dub. After 6 patches they started coming out pretty clean - no need to dirty a brush yet.


Let's see what the bore looks like.

Chamber is pretty pristine.


Side view of the jump and throat.


Some residue left. But I'll scrub and lap with JB paste - there is other work to do too before installing.


A tool mark? - not uncommon.

Both these were taken from the same spot - I measured it. Given the reflection in the bird's eye pic could this be a sliver of copper from the proof round that I dislodged from the lands? After pushing tight, dry patch through I could not find it again. The pic also prompted me to run a barrel straightness test - a 0.2996 pin gauge, 2.5+ inches long goes all the way through the bore with no resistance. A 0.300 minus pin barely starts at the muzzle.

I was worried about the muzzle and crown since it was sticking out of the wrapper...but it is in fact pristine.


Now some gauging. Muzzle is at .300, and a .3 minus gauge just starts. Chamber end shows just a touch over 1, which is very normal for a new barrel. I've seen a few brand new criterion barrels at ~1.5+ before finish reaming.

Don't forget to push a patch of oil through the bore before moving on.

A .790 minus pin gauge is used as a go-gauge on the gas port. It just slips in, but doesn't drop all the way into the bore. Likely a burr in the bottom of the gas port. You can just make out slight jagged edge here, and a you can feel it with a tight fitting patch.

Pretty normal, and usual treatment is to just shoot it out, but sometimes that makes the edge of the whole come out looking ragged. No loss in functionality, but we can do better. Chase the gas port by hand with a 0.790 reamer in a pin vise and the bur goes away. Still a little cosmoline in there that needs flushed out. If you don't have a 0.790 reamer, a 2mm drill bit will work too - turn it by hand though. No power tools.
Looks pretty now. Can't feel it with a patch, and the go gauge drops easily all the way in, and 0.791 pin does not even start.


It took me longer to write up this post than it did to take this out of the wrap, and my keyboard is dirtier from the chips I'm snacking on while typing than my workbench got whilst doing this barrel. If you have a wood stock wrapped in waxy cosmoline (like back when you could pull a mosin from a crate for $40) DO NOT use kerosene or any petroleum product on the wood. Scrape off the majority, then use a heat gun or hair dryer and turpentine to brush it out and wipe it off.

EDIT: I should mention - don't put your kerosene and grease soaked towels in the trash. I stuff mine in an old tin soup can, then top it up with soapy water and let it sit on the bench overnight. I take out the paper towels the next morning and throw in the trash.

[RCS]

Marlin barrels were used during the Korean war period on production Springfield M1 rifles in the 4,2 and 4.3 serial number range. This was because
of a shortage/problem with Springfield barrels.

[browningautorifle]

a shortage/problem with Springfield barrels.

What problem, were they not getting straightened after heat treating?

[ssgross]

this one looks very nice. That thing that looked like a tool mark was indeed just a fleck of copper imprinted with the tool marks on the lands. In fact, I couldn't find it again because I had moved it to the chamber when I passed a patch. I found it there, sitting in the corner at the end of the chamber's neck, and was able to pull it out intact. I was able to view it under a microscope. Fascinating. First time I've ever seen that!

Has anyone seen an arsenal rebuild with a marlin barrel? I would have thought the contract was designed to put as many older m1's back in to service as quick as possible, since this would be much faster than newly manufactured.