CMP Forums

CMP Forums (http://forums.thecmp.org/index.php)
-   Mann Accuracy Device (http://forums.thecmp.org/forumdisplay.php?f=102)
-   -   Springfield 1903 Match Rifle with barrel marked Mann. (http://forums.thecmp.org/showthread.php?t=217180)

RCE1 10-04-2017 03:36 PM

Springfield 1903 Match Rifle with barrel marked Mann.
 
I inherited this rifle and know nearly nothing about it. The guy I got if from got it from a guy who got it from a guy...

Anyway, it has a target stock with forend accessory rail mounted. It is marked 25 CAL - MANN CHAMBER on the barrel, which is very heavy. It's has scope blocks mounted, an adjustable trigger and seems really well made. I was wondering if anybody knows anything about this rifle, especially the barrel.

Luckily, it came with dies and some loaded ammunition. It appears to be chambered in 25 High Power, which I believe is the same as .250 Savage or .250/3000.

https://imgur.com/W0eYYkW

https://imgur.com/nxZIPo8

this links to an album of pictures I did of it recently.

https://imgur.com/a/ubMf4

mhb 10-04-2017 04:18 PM

It is a nice looking target rifle...
 
But you need to be cautious about the proper ammunition. The actual chambering does not seem to be marked on the barrel, and the ammunition and dies which you got with the rifle MAY be correct for it, but the first thing you should do is make a chamber cast to verify the dimensions of the chamber. You need to know that the Mann chamber (named after rifle ballistics experimenter Dr. Franklin W. Mann) is made with a very tight neck - so much so that it probably would not accept factory loaded ammunition - and the cases for use in a Mann chamber were neck turned so that the diameter of the neck of the loaded cartridge is as near to the actual neck diameter of the chamber as possible - there is very little if any clearance at that point to permit expansion of the neck when the round is fired, with the purpose of keeping the bullet as closely aligned with the throat and origin of the rifling as possible. This condition results in very high pressures if standard loads are used, so caution must be exercised in working-up loads for use in a rifle so-chambered.
There is no evidence that the tight neck produces better accuracy than an otherwise excellent chamber suitable for cartridges of standard factory dimensions.
If you intend to shoot the rifle, and don't want to go to the extra work of preparing proper ammunition for the Mann chamber (asuming that the chamber actually does still have the tight neck), you might wish to have the chamber altered to factory spec. - this might be accomplished by simply reaming the neck of the chamber, but the chamber cast is the only way to determine exactly what the dimensions of the chamber currently are, and how best to proceed.

mhb - MIke

RCE1 10-04-2017 11:20 PM

That's interesting about the tight necks. I wonder how many gunsmiths were making MANN chambers and in what time frame was this considered competitive. Modern day bench rest shooters neck turn their brass, but none that I know of strive for zero clearance. I believe my friend would turn for about .0015-.002"release. He neck turned everything, from .17 to .45. Even his varmint loads. He was a true believer in the machined surface. All his reamers are tight necked.

All this being said, I think if he did fire this rifle it was decades ago and he would have been shooting cast bullets in it. Maybe in the 70s, but this gun is older than that, don't you think?

mhb 10-05-2017 09:25 AM

Unless...
 
Quote:

Originally Posted by RCE1 (Post 1644811)
That's interesting about the tight necks. I wonder how many gunsmiths were making MANN chambers and in what time frame was this considered competitive. Modern day bench rest shooters neck turn their brass, but none that I know of strive for zero clearance. I believe my friend would turn for about .0015-.002"release. He neck turned everything, from .17 to .45. Even his varmint loads. He was a true believer in the machined surface. All his reamers are tight necked.

All this being said, I think if he did fire this rifle it was decades ago and he would have been shooting cast bullets in it. Maybe in the 70s, but this gun is older than that, don't you think?

You can find a maker's name on the barrel, it is not possible to tell exactly how old the assembly is. The rifle's stock and overall appearance seem to belong to the post-WW2 era; the stock is marked where the later-type Lyman 48 receiver sight was once installed. It is interesting that the cocking piece appears to be the headless NM style of ca. 1929. It would also be interesting to know what sort of adjustable trigger is installed.
Your clear photo of the muzzle shows coppering on the top of the visible land, so jacketed bullets were shot in it, whether cast ones were or not.
FWIW, my understanding of the Mann neck is that it was always an experimenter's tool, and never had any serious competitive application.
You are correct that modern BR practice does not include a super-tight neck, and you may well believe that, if it offered any slight advantage, the BR world would have adopted it.
I have made and chambered a number of barrels with tighter-than-standard necks, and always engraved them with the actual neck diameter and the warning that they are 'Not For Factory Cartridge' - but I have never made a true Mann-style chambering, as no one ever asked for one.


mhb - MIke

RCE1 10-15-2017 01:26 PM

I took it apart yesterday and took a bunch of pictures of the inletting and the trigger.

Lots of new closeups for those interested.

https://imgur.com/a/ubMf4

mhb 11-18-2017 01:48 PM

The rifle...
 
has been extensively gunsmithed. The trigger is a fully-adjustable commercial type, but I can't identify the manufacturer.
The bolt has been modified by altering the cocking cam, presumably with the intent of shortening striker fall. The cocking piece is not the headless NM type, but a much-modified issue type, with evidence of welding and grinding, probably to work properly with the commercial trigger and the modified bolt.
The receiver has been notched for an altered bolt handle.
The bolt appears to have a bevel in the firing pin hole (possibly from a lathe center?), which is an undesireable condition and can result in a raised ring on the fired primer, and possibly contribute to pierced primers.
The stock has been bedded to the barreled action with some attention to proper fit (the blue substance on the wood surfaces was used to check fit as bedding progressed), but the overall work of inletting is fairly rough.
More photos of the other parts of the rifle would permit more thorough evaluation.

mhb - MIke

Old Chief 11-21-2017 03:31 PM

Mann Barrel
 
That's one beautiful rifle you have there but it's definitely not made from a Mann Accuracy Device. The average Mann Device had about a 22" very large barrel.

RCE1 12-11-2017 04:23 PM

Quote:

Originally Posted by Old Chief (Post 1656744)
That's one beautiful rifle you have there but it's definitely not made from a Mann Accuracy Device. The average Mann Device had about a 22" very large barrel.

I figured that out eventually. I suppose this thread is not in the right place but I appreciate the input.

I've been trying to find out a bit more about this rifle as I inherited it from my father in law, who had inherited it from a friend of his. All I know about it is that it's got a barrel clearly marked as having a Mann chamber and it is chambered in .250 High Power, which I believe is the same as .250 Savage. I have not taken a chamber cast of it, but the rifle includes a few loaded rounds and a set of dies marked to go with it. The work done to it seems to have been carefully done, but I've not fired it.

From what I understand, the Mann chambers were designed with a very tight neck (like zero clearance). The guy I inherited it from was in the habit of neck turning all rifle brass and all his reamers required it. I don't know that he ever fired this rifle, but he did have a strong interest in cast bullet target shooting and also loved the .25 cal.


All times are GMT -5. The time now is 07:32 PM.