Marlin Rifle Barrels.......A Question

[beechbum444]

I have a question for the tinkers and gunsmiths out there.......On the Marlin actions, the 1893s, 1894s, 1895s, 336s and so on.......Do you think that from a production/ machining standpoint the barrels are short chambered, screwed into the action, torqued down and then finished using a finishing reamer and the bolt to properly headspaced on the round........OR......do you think that the tolerances are so tight, that the barrels are chambered to the correct headspace are screwed in, torqued down and both have the sights line up and the cartridge headspaces with no slop....kinda like an AR barrel going right in without having to check a headspace....The second would be cheaper from a labor standpoint.............any thoughts appreciated ......regards

[Nobade]

I have never seen one that didn't have the shoulder portion of the chambered blued so I would say they cut them to final dimensions before installation. They have square threads and will come to a positive stop, so it's not hard to do it that way. As for tight tolerances, that doesn't apply to a Marlin. Good enough is more appropriate.

[Shawlerbrook]

Waiting for John Taylor to give us the answer.

[MostlyLeverGuns]

Marlin headspace can be adjusted by changing the fit of the locking lug. If you have enough different sized locking lugs you can find one that sets headspace where you want it or you can start with a new lug and fit it to tighten headspace. Most of the Marlin's I have tend to have 'GENEROUS' headspace. Threads are indexed for fitting to the receiver with all the chamber, sight, extractor and other barrel cuts made and headspace set after the barrel is tightened.

[JimB..]

There is an old Marlin employee on here, his name escapes me. He previously posted that barrels were finished and then mounted to the receiver.

[W.R.Buchanan]

The barrels are finished before they are installed and with the machinery they have now it is not that hard to time them so everything lines up when they are installed.

Randy.

[John Taylor]

Jigs and gauges are used to check the fit of most parts before assembly. Mass production is all about saving time so there is little hand fitting of parts.

[2152hq]

I worked at Marlin in the very early 70's. The bbl's were finished chambered, blued and ready for assembly.
The assemblers would adjust headspace by fitting the locking bolt to the individual rifle.
A simple jig was at each assemblers bench used to trim the locking bolt as needed.

The new locking bolt was first placed in the rifle and the bolt closed on the go gauge.
The assembler using their experience would view the position of the closed lever to the bottom tang.
That distance tells them how far they needed to trim the locking bolt down to allow the bolt to close on the Go gauge.

Taking the bolt out and place it in the Jig, the hardened steels guides being adjustable, simple hand filing made keeping the locking surface of the locking bolt square while trimming very small amts from the surface.
A cut and try type of fitting.

This was at the North HAven factory, New at the time, but the tools and fixtures were theold ones brought up from the New Haven plant.
I'd guess it was done was the same way in years past as well.

I still have my 'set' of Head Space gauges for the 30-30 & 35.
Mine I used in the Repair Dept there.


I just used the 30-30 to re-set the HS on an 1893 SRC restoration/rebuild that had excess HS.
That one I shimmed the bolt face on it. That brought me back to just barely not closeing on the GO gauge.
A little work w/a 30-30 Finshing Reamer and the GO gauge got me back to a good chamber spec once again.

[beechbum444]

True craftsmanship…..

[shootrj2003]

I’m building a 30 AW that was damaged ,I was lucky to get a NOS unused 30/30 barrel from the real Marlin stock it was finished and blued ,only requiring a maybe 1/8 th turn to snug up and the dovetails are perfect ,only thing is I’m rust bluing the whole gun so i have to strip that blue ,that beautiful new JM Marlin blue so everything matches.

[M-Tecs]

I worked at Marlin in the very early 70's. The bbl's were finished chambered, blued and ready for assembly.
The assemblers would adjust headspace by fitting the locking bolt to the individual rifle.
A simple jig was at each assemblers bench used to trim the locking bolt as needed.

The new locking bolt was first placed in the rifle and the bolt closed on the go gauge.
The assembler using their experience would view the position of the closed lever to the bottom tang.
That distance tells them how far they needed to trim the locking bolt down to allow the bolt to close on the Go gauge.

Taking the bolt out and place it in the Jig, the hardened steels guides being adjustable, simple hand filing made keeping the locking surface of the locking bolt square while trimming very small amts from the surface.
A cut and try type of fitting.

This was at the North HAven factory, New at the time, but the tools and fixtures were theold ones brought up from the New Haven plant.
I'd guess it was done was the same way in years past as well.

I still have my 'set' of Head Space gauges for the 30-30 & 35.
Mine I used in the Repair Dept there.


I just used the 30-30 to re-set the HS on an 1893 SRC restoration/rebuild that had excess HS.
That one I shimmed the bolt face on it. That brought me back to just barely not closeing on the GO gauge.
A little work w/a 30-30 Finshing Reamer and the GO gauge got me back to a good chamber spec once again.

Thanks for the firsthand account.

On a side note indexing and timing with today's CNC equipment is very easy compared to the old days. That being said timed and indexed barrels have been the norm for a very long time.

I don't have a clue as to when timed barrels and actions became the norm but the 1903 Springfields and 1917 Enfield's are all fully chambered and screwed together until the index mark lines up.


....kinda like an AR barrel going right in without having to check a headspace....

On AR's the barrel extension fit is what determines headspace. They are timed and indexed and inspected by the manufacture. Tolerances are tight enough that the end user should not need to check themselves. That being said out of spec parts have been known to be shipped out so it is recommend checking headspace on new barrel extension/bolt combinations.

[lcclower]

Experience with 2 of 3 Marlins:
1895, shot like a champ, used, right home fromm the gun show.
1894, .44Mag, microgroove, slugged .429 to .433 and was egg shaped under the roll marks. Got a 6 groove replacement barrel, Marlin, was not so out of round but slugged .430-.431.
.30-30, did nit shoot for beans, I dragged it out of the safe and slugged it, microgroove .310 to .312. SHot .312 cast with gas check good enough. Eggg shaped under the roll marks again.