M1 Garand @ 200

[Onmilo]

I haven't actually handled one of the pull through reamers but am guessing thay are machined at the back of the cutter same as a headspace gage.
Pretty laborious as you cut one turn, wipe and relube the reamer and repeat until the bolt sets down into the locking lugs with a bit of firm thumb pressure.
The stripped bolt stays in the guideways but you don't have to keep it against the cutter as you make each turn.

 

[Reloadron]

Onmilo, thanks for that info! So I assume that the finishing reamer functions as a gauge while it is cutting? Is that what you are camming the bolt against or are you having to stop and use a headspace gauge? If it allows you to ream until the bolt drops in, that is one slick set-up!

Pictured below are a few exhibits. The upper reamer is a pull through 30-06 Springfield with the thrust bushing attached to the rear. The lower reamer is a pull through 308 Winchester reamer and I left the thrust bearing off so it can easily be seen. The thrust bearing is precision ground.

Not shown is the "T" Handle Rod. The reamer is inserted into a short chamber. This type reamer is a finishing reamer only. The T handle rod is inserted into the muzzle and screwed into the chambered reamer. The bolt is allowed to come forward against the thrust bearing and the T handle is rotated with cutting oil added to the chamber.

A typical short chambered barrel is generally within about .010" of being the correct headspace and generally only a turn or two is required as constant gentle pressure is applied to the bolt. When the bolt closes that is it.



The below image shows a few M1 Garand barrels. The lower barrel is a full contour 308 Winchester barrel. If you look real close you can see where it is stamped "Short Chamber". So we would install the barrel making sure we get it correctly indexed and when that was done we would use the pull through reamer for our final chamber cut for correct headspace.



Hope that helps explain the pull through reamers and how they are used.

Ron

 

[Onmilo]

Nice clear picture of the pull through reamer.
I am guessing it is a two man operation if you must hold the bolt down against the reamer as it is turned?

I was taught to run the go gage into the chamber and measure the stand off with a depth gage and make the final finish cuts in three passes, stopping the headstock after each pass, backing the reamer out, cleaning and reoiling it and remeasuring before the next pass.
I don't believe I ever needed to go more than .018" to achieve headspace on any rough chambered barrel either.

This techniquie won't work on USGI chrome lined M14 barrels either.
You must cut or roll the barrel shoulder to achieve headspace with these barrels but the technique is exactly the same for non chrome lined M14 match barrels.

 

[Reloadron]

Onmilo, I do believe that covers it. Done right you will get within .001" and as you mention the pull through can get a little awkward. Gently was always the key word and when stopping a turn you want to come to a gentle stop reducing pressure as you stop.

It is easier to get a chamber cut (finished) than get the barrel correctly indexed. Like you mentioned earlier you don't want to pass the correct index. With a breaker bar and hanging on the receiver wrench that is easy to do.

Ron

 

[Onmilo]

If anybody is reading this now besides Ron and me and is curious what we are talking about,
you roll the barrel shoulder when the barrel sets past top dead center index.
You use a tool that looks like a knurling tool without the knurl cuts on the roller to set back and displace metal from the barrel shoulder edge.
Amount of set back is determined by measuring the length of overtravel past top dead center and halving that dimenstion, then rolling that halved amount of dimension material back.
You would cut the barrel shoulder if the barrel sets short of top dead center and the technique for determining amount of material to remove is the same.

In other words,
If the barrel sets short or long by say, .030", you would cut or roll displace .015" of material to achieve TDC index.

 

[119er]

So, if the barrel passes index, you would roll metal from the edge to achieve contact sooner? Thus getting proper index, or close enough to remove a little more?

Thanks for the images too, Ron. I wish I had the time to take some gunsmithing courses.

 

[Reloadron]

So, if the barrel passes index, you would roll metal from the edge to achieve contact sooner? Thus getting proper index, or close enough to remove a little more?

Thanks for the images too, Ron. I wish I had the time to take some gunsmithing courses.

Yes, that is what it comes down to. The M1 Garand barrel if you look at the images I posted uses a 10 pitch thread and the threads themselves are similar to an acme type thread.

As the correct index is approached tightening the receiver on the barrel things get tight and thread crush begins to happen. With threads like this if we pass the correct index we can't just back the receiver off. You are pretty much screwed in a word. To fix things we try and roll some metal on the barrel shoulder step. Than enables us to try again.

The whole trick is to try and avoid that scenario.

Ron

 

[Onmilo]

Yeah, If you lucky enough to have a whole bin full of barrels to try fit, your life has just gotten easier.

 

[119er]

Can you imagine how much an M1 would cost to produce today in the US as it was done originally? I think that the Springfield Armory Inc. ones from several years ago were cast receivers. Plus we now have CNC machinery to speed up the process and reduce the amount of fitting needed. I can't remember what those went for.

Makes building an AR-15 look like baby food!

 

[Reloadron]

Can you imagine how much an M1 would cost to produce today in the US as it was done originally? I think that the Springfield Armory Inc. ones from several years ago were cast receivers. Plus we now have CNC machinery to speed up the process and reduce the amount of fitting needed. I can't remember what those went for.

Makes building an AR-15 look like baby food!

I can tell you this much.

Cost of a M1 Garand during the war years:

July 1941 to July 1942 $41.93 EA. They made 417,581 of them.
July 1942 to June 1943 $35.21 EA They made 852,651 of them
July 1943 to June 1944 $28.28 EA They made 1,155,408 of them.
July 1944 to June 1945 $27.74 EA They made 880,321 of them.

Those numbers were taken from Springfield Armory Statement of Expenditures. Worth considering is how many of the early parts were milled and the later parts were stamped. Fewer man hours and less waste resulting in lower cost.

I can't imagine what it would cost today to manufacture the early version of the rifle.

Ron