M1 Carbine Herlo Barrel

I am new and this is the first post. I bought this barrel in 1997 from KY Imports in Louisville, KY. Bought it the same time I bought a Bavarian import Carbine. The M1 is great, an Underwood.

Later I bought a parts kit from someone, all new, trigger housing and all components for same. Can not remember who. Same for a brand new surplus stock complete.

In any event I have been on the outlook for a receiver to build a complete gun.

Now that I am getting into the project, I find the barrel is suspect. I recently got a copy of Jerry Kuhnhausen's book The U.S. .30 Caliber gas operated Carbines, A Shop Manual. Great book! I am reading it through and learning a lot.

Can anyone tell me what I have here and what are the chances I will be successful?

Now I am going to try and post pictures. Ask any questions.

Appreciate any help. Bill Ricca offered that he had some luck (about 90% good) of a non chromed lot but did not know if this one is chromed.

Disclaimer: The following is personal opinion, assume the value may be worth only what you pay for it.

Those interested in collecting only will tell you to find a surplus barrel with proper markings etc.

Last year I re-barreled a carbine to correct problems, perhaps caused by it being modified by previous owner to shoot after being modified by previous-previous owner as a movie prop. I decided to use a new commercial barrel. They are available from a few sources. These are short chambered, and long shouldered. I do not have a lathe, so I had to hire a gunsmith to adjust the shoulder. You then need to chamber ream etc. I bought a pull through reamer (I since have rented it out 2 times, once to the gunsmith who did the barrel work for me). The result was a nice looking carbine that shoots as accurately as any I own.

Since it is not that hard to screw a barrel into a receiver, if the Herlo barrels do not require you to hire a smith with a lathe, go for it and see if it shoots well enough for you.

By the way, a careful look at the chamber end may enable you to see if it is chrome plated.

That is my plan. I do have a lath but not the experience to do the work. I have a friend who owns a large plating operation and I did plating at GE back in the 70's. I can strip if necessary, my thought though is that the lot that was chromed is as listed in U.S. Carbine A Shop Manual by Jerry Kuhnhausen, he lists the 8448416 lot from 12 of 72 as being the chromed lot. What is still unknown, how many lots did they make? Evidence would indicate at least 6?

Have to add, a muzzel wear gauge checks this brand new barrel at "1". I "think" this is fair as the tolerance is .300 + .002. I do not know how accurate the gauges are, mine is a Fulton and new (used 4 times).

Does anyone know what the design parameters of the gauges? Anyone have a print? We all know a .300 pin will not enter a .300 hole, if a .2999 pin does it is tight depending on roundness and such. When I measure the gauge (bought 2 just to check them out-one to the other). They are about the same. I have to assume the gauges are screw machined off with the body large and the groves cut, then ground at a taper from end to end? One of mine is out of round by a few thenths or less. I am going to check it out using ring gauges just to check what it is doing. I do not have here at my house, have to visit a grind shop to have access to more accurate tools.

Like I said, I am new and just learning.

I have a finishing reamer inbound to set up the headspace on my new non-chrome Herlo bbl. Based on my Garand re-barreling experience, I prefer to use the pull-thru reamer after the barrel is installed, however pull-thrus are not available for the .30 carbine at present.
I'm going to use a technique to hand ream the chamber off receiver as described on this board by Gus Fisher. This involves the following:
-with the barrel at a hand tight position of 45 deg off TDC (mine is 40 deg), remove the bbl and ream the chamber to a point where the bolt will begin to close on the "no-go" gauge
-when the barrel is then installed and torqued to TDC the headspace will be correct on both the "go" and "no-go" gauges

All of the 84xxxxHerlo barrels are chrome lined. The 55xxxx barrels are not. It should also be mentioned that the non-chrome barrels have varying twist rates and many are not fast enough to stabilize the bullets.

Roger that. In another post I mentioned that I had checked the twist rate in my non-chrome 55xxxx bbl and found it to match that of a Saginaw bbl. I think I just got lucky on that part.

Just got 5 of these NOS, and 5 NOS IAI receivers. The chromed ones have
visable color difference at muzzle. However, they are all complete. Sight,
piston, nut and T3 barrel band. Hand tightened them onto receivers and
they fetched up at 10 o'clock. 40 to 45 degrees off TDC. This tread helped
a LOT.

Just be aware that the chrome barrels are known for having the chrome start flaking off causing some problems. This was just one of a bunch of problems with all of the Herlo barrels. That is why they were all rejected by the government.