How to evaluate a milsurp rifle barrel?

[raindog]

What are steps to go through to evaluate how good a rifle barrel is? I'm thinking specifically of milsurps.

You get a milsurp rifle and want to know how good the barrel is. I know people talk about "dark bores" but heck the milsurps I've got were mostly opaque bores because they're filled with cosmoline :-) I've never found a barrel that didn't clean to a shine - or at least what I would no longer describe as anything close to "dark". Some take a lot more scrubbing than others of course...

So imagine I've got a typical milsurp bolt-action. I de-cosmo and clean it up.

(1) I look down the barrel (borelight at one end). I see spirals. What else should I look for? Honestly most rifle barrels I look down show spirals - from brand-new 21st century hunting rifles to 1890s Mausers. Would better barrels show tighter, more hypnotizing spirals?

(2) I could slug the barrel - would a slug from a good barrel show more grooves than one from a bad barrel?

And of course, I could just shoot it and see how it does. It usually takes me a while to adjust to a rifle and I'm never sure how much is my ability (or lack thereof) verses a rifle's deficiencies.

It'd be nice if there was a way to evaluate before buying but (a) I tend to buy over the Internet anyway, and (b) barrels are full of cosmo.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[jmoore]

If it's not full of cosmoline, then you know to look especially well. I can assure you the first sewer pipe you encounter won't be hard to recognize. Usually because some Bubba didn't clean with water before putting his cheap rifle (shot with cheap surplus ammo from the '50s) in the closet...

[rangerbluedog]

If you're really familiar with the particular rifle in question you will know the approximate depth of the rifling grooves.
Look for shiny bore, sharp edges on the rifling, depth of rifling, use a bore gage in the muzzle end to check for erosion (if you don't have a bore gage, stick a bullet in the end of the barrel - if it falls in, the bore is worn! lol.)
There are gages to check chamber erosion - use 'em if you got 'em. Otherwise do a visual with your bore light. Look for pits a few inches from the chamber especially.
Check for dings, dents, & dingleberries on the crown of the muzzle.
I look on the outside too - where the metal meets the wood. This is where rust begins. Look also where the barrel screws into the receiver for cracks and rust.
I hope this helps.

[Patrick Chadwick]

This is going to take some time to put together - I may have to break off and continue tomorrow.

Apart from slugging the bore or making a chamber cast, all the steps described here can be applied in a shop, on the counter, thus considerably reducing the risk of getting a dud.
A rifle that passes all these tests is worth a serious test with ammunition matched to the results of the tests. Or immediate purchase if the price is right.

Basic kit
1) A yard/meter length of threaded brass (NOT steel) rod, 6x1 mm or 1/4"x24 or 26 tpi. And 2 nuts to fit.
2) A 6"/150mm vernier caliper/slide gauge.
3) An empty cartridge case of the appropriate chambering.
4) A bullet of the correct caliber. The longer, the better!
5) A felt-tip marker pen
6) A watchmarkers eyeglass.
7) A white felt cleaning wad or similar material to make a simple, movable bore plug

First visual check
As you have already discovered, the popular dealer's and auctioneer's phrase "with a dark bore" is totally uninformative, and to my cynical mind is just a disclaimer in case the rifle turns out to be a dud. I have found excellent bores that were "dark" - full of muck, grease etc, as you have noted. And some of the WORST were super-shiny. Because they had been cleaned to death and had bell-mouthed muzzles.
Believe me, unless you are an experienced barrel-maker, you can NOT judge a bore adequately just by looking down the barrel.

a) Muzzle wear
Use the marker pen to ink over the start of the ogive on the reference bullet, and give it a few seconds to dry. Insert the bullet into the muzzle. Straight, of course! If the bullet simply slides down the bore, then you need progress no further. The bullet should stop at a point where you can see that the curve of the ogive has commenced. Push lightly and twiddle the bullet around. Remove the bullet. The transition bore/crown will have rubbed a bright ring around the ogive. Use the vernier to measure the diameter at this point. This is a tricky measurement to make "over the counter", so I advise some practice at home with a known good bore so that you get a feeling for how accurately you can conduct this measurement. If that is OK, procedd to...

b) Crown and muzzle inspection
Insert the plug material 7) into the muzzle and push it down the bore about 1/". This provides a good diffused reflection to illuminate the bore at the muzzle, and enables you to make a visual examination of the crown and muzzle. It is the method I used to make this photo:

Attachment 39435
- and you can just see a corner of the felt.

Chipped/corroded crowns are common, and easy to deal with

Before
Attachment 39437

After
Attachment 39436

- So don't let yourself be put off by a little surface rust! What really matters is that the rifling carries right up to the crown. If you cannot see any rifling in front of the plug, as in the first photo, then it might be possible to salvage the bore by counterboring, but that depends on how far back the rifling is worn.


Check throat depth and head clearance

The basic tool kit listed above can be used to check throat depth and head clearance (not strictly the same as headspace, but IMOH more useful in the real world!). The method is described in detail with photos, here:

https://www.milsurps.com/showthread....head+clearance

I tried to copy the text + photos into this post, but ended with complete garbage, so please follow the link!

That's enough for the moment

[jmoore]

That's enough for the moment

But wasn't the whole notion of finding milsurp after milsurp still cosmolined enough to set you back on your heels? Aside from freshly overhauled Mosin Nagants is there such a thing anymore???
Not counting the poor worn and beaten-up dogs that were drowned in grease after death which seem to litter the planet.

[Patrick Chadwick]

Aside from freshly overhauled Mosin Nagants is there such a thing anymore???

My Enfield NoIII Mk V was cosmolined. Also the Martini-Henry Mk IV (OK, "yakolined"). Both had been kicked round the arsenals for decades, but were internally mint. And some of those "drowned in grease after death" have, I suspect, have been treated thus to hide the rust and make prospective buyers think they are "fresher" than they are.

[Oscarflytyer]

I don't want to over-simplify things, but... I have a bunch of milsurps in the safe, and have had numerous others pass thru my hands. Never had a really bad shooter. None of mine have been sewer pipes, but I certainly haven't put a lot of effort into their evaluation. I will run a patch down them to remove the dust/cosmoline/gunk. If the lands/grooves are high and look sharp, no pitting is observed, the crown isn't beat up and the muzzle doesn't swallow a bullet, it will go home with me. I might even take a dinged crown - a brass screw and some valve lapping compound will do wonders! And due to corrosive primers that these rifles shot over their lifetime - I don't care if it has a dark bore. I kinda expect it...

Here is my logic and philosophy. None of these milsurps are expected to shoot match grade groups, espec with my old 50 yo eyes and open sights and old milsurp/corrosive ammo. You have to remember - these were designed to shoot minute of soldier! I am NOT buying a milsurp to shoot MOA groups at 100 yds with irons. I am buying a piece of history to enjoy and shoot and have fun and expose my sons (5 of them!) to history. For us, it is way more about the history and where the guns may have been and through and just getting to shoot them. It is the experience for us.

Having said all this, I have yet to get an aweful shooter and some that shot very well. Just bought an M1 shooter. $525 for a field grade w/ TE=3 and ME=2. Great fun shooter! Lots of quality time with the boys!