A mauser for cast bullet work

[frnkeore]

Frank, we understand you are the end all expert and great guru of all things firearm related and go to great lengths to prove me wrong. However there is much difference of opinion as to what constitutes the "leade", the "free bore", the "case mouth taper" and the "throat" overall. The general accepted term for the beginning of the lands/rifling (again two different terms meaning the same thing) is most often referred to as the "leade" these days. Note I referred to it as "long throat (free bore section)" and not the "leade".

If you refer to Ludwig Olson's book on Mausers and the NRA publications written by the NRA technical staff you will find Mausers, including the 8x57 Mausers, have a "throat that is approximately 4 1/2 calibers in length". Many refer to that portion of the throat as the "free bore" whether you do or not. The fact is it is there, particularly in the 24/47 the OP is interested in.

However, in one sense you are correct in that the "chamber" has no freebore as it doesn't even though I did not say it did. It is the "throat" that has the freebore, just as I said.

Larry Gibson

No Larry, I'm not a guru, I just like to post accurate info if I have that information available. I design bullets to fit the throats of chambers so, I'm familar with chamber design. I also design my own chambering reamers for the rifles that I build.

So people don't get confused regarding a rifles throat. I'll do my best to explain it.

The throat is everything from the end of the case mouth, to where the leade brakes through the lands in the rifling. I've denoted the Throat by the blue lines that you see in the following drawings.

A freebore (shown in the 6.5 Rem Mag drawing) starts at the end of what Larry calls "case mouth taper" and is almost always a parallel cylinder of what ever length the designer thinks would be optimum for support, alignment and to set the proper COAL. I've denoted the freebore by the red lines.

One other use of it is to retard pressure build up, as in the case of the Weatherby cartridges. His freebore is usually much longer for that reason than other rifle chambers.

For clarification, the the leade can make up the entire throat of a rifle, as in the case of the 30/30, 32 Win Spec. and 38/55. Thoughs chambers start their throat at the end of the case mouth, with a single, continuous angle that transitions all the way through the lands.

Now the leade as depicted in most other chambers is a angular cut that can start at the end of the case mouth transition angle or can start at the end of the freebore, in either case, it cuts all the way through the lands and can even have multiple angles, as in the case of the 303 British. This I have depicted by yellow lines. For the 8 x57, the yellow line at the end of the leade and at the end of the throat is the same with the yellow drawn through the blue line.

If you measure the 8 x 57's leade, you'll find it to be 2.72 calibers long.

I hope this is helpful in explaining the throat and if you ever have a reamer made for yourself, either chamber, neck and throat or just a throating reamer, these are the terms the reamer maker will be looking for.

Frank

[Larry Gibson]

That's pretty darn good Frank, you just eloquently explained exactly what I said the "throat" consisted of.

However, we see once again you've arm chaired it and are simply copying some drawing or data from the internet or some other source. I suggest you actually do something yourself for a change and make chamber casts of numerous M98 Mausers spanning the time period from the early 1900s to the 1950's as I have. I think you will find the throats of those rifles to be somewhat longer than the commercial SAAMI chamber specification drawing you are quoting from.

Let me quote from the NRA Technical Staff and Ludwig Olson (Mauser Bolt Rifles) regarding this;

"A long bullet lead, or throat, cut on a straight taper, in conjunction with a small amount of free travel, was provided to prevent excessive chamber pressure. This feature is quite evident upon visual examination of German military barrels and gives the impression that the chamber throat is badly worn. Length of the lead or throat in military barrels is 4 1/2 calibers."

Understand that? That is for "military barrels". Rifles with military barrels are the topic of this thread. Understand that? Your drawing and fine explanation (says the exact same thing I said about throats) is based on the SAAMI specifications for a commercial chamber, not a military chamber. Understand that?

Once again, thank you for your quite detailed explanation of the "throat" of a chamber as I described it and the basic separate parts there of. I am a bit confused though as you state; "I design bullets to fit the throats of chambers so, I'm familiar (SP corrected) with chamber design. I also design my own chambering reamers for the rifles that I build." Are you saying Paul Mauser enlisted your aid in designing the throats for the 8x57 chamber used in military rifles that were made probably before you were born? If not then how is what you design, based of the SAAMI chamber specifications for a commercial chamber, relevant to military chambers designed in 1905/1906 for the 8x57 cartridge and chambered in 118+ million M98 Mausers?

The discussion here is about military chambers Frank. Understand?

Larry Gibson

BTW; here are SAAMI's definition for the terms under discussion. They make it clear as mud.

CHAMBER LEADE
The conical part of the bore between the chamber and therifling. Also called Throat or Ball Seat.

BALL SEAT
See Leade.

LEADE (LEAD)
That section of the bore of a rifled gun barrel locatedimmediately ahead of the chamber in which the rifling is conically removed toprovide clearance for the seated bullet. Also called Throat or Ball Seat.

THROAT
See Leade (Lead).

FREE BORE
A cylindrical length of bore in a firearm just forward ofthe chamber in which rifling is not present. Associated with bullet jump.

FREE TRAVEL
See Bullet Jump.

BULLET JUMP
The distance that a bullet must travel from its position atrest in the cartridge case to its initial engagement of the rifling.

[frnkeore]

That's pretty darn good Frank, you just eloquently explained exactly what I said the "throat" consisted of.

I fail to see where your explanation comes anywhere close to what I discribed or showed anyone what you where refering to.

I'm taking it that Paul Mauser must have channeled through you, when he designed rifles and chambers.

Can you please give us a FACTUAL account as how the SAAMI chamber spec's came to be? Where they perhaps based upon Paul Mausers design, or did they just "make them up". BTW, I doubt if Paul had anything to do with the 8 x 57's design. It was designed by the "Commision" that designed the GEW 88. Paul was upset by that one!! I think his first chamber was the 7.63 x 53 in 1889.

We all understand that military, especially war time, rifle production can be a bit loose on adhering to tolerances but, the basic chamber design remains the same and if your going to "fit" a bullet to a chamber and throat, you use the chamber design, unless you have a paticular rifle in hand.

For your information, I have 21 chambering reamers (including chamber, neck & throat and throating). 12 of them made to my spec's by either PTG or Hugh Henderikson (sucessor to Keith Francis), both are near by. The others are by various makers.

I'm sure that we would all be interested in the pictures and dimensions of your personal collection of chamber castings of all military calibers that you have and your description of how you accurately measured them.

Do/can you understand that? I can try to break it down to simpler terms if you like.

Here is hoping you understand,

Frank

[Larry Gibson]

Oh Frank, you are just so clever! However, you "fail to see" so much because of your heartburn for me as you continually "fail to see" the forest for the trees.

Obviously you have failed in your research as the NRA technical publications and Ludwig Olson point out;

"The German Proof Law of 1939 covering commercial arms specifies that this bullet lead should be not less than 35mm or 1.377" long for the 8x57JScartridge. In this country (U.S.A.), cartridge and chamber dimensions for commercial small arms are standardized by a special committee of the Sporting Arms and Ammunition Institute (SAAMI) which furnishes the industry with drawings indicating maximum and minimum chamber dimensions. The SAAMI drawing for the 8mm Mauser chamber indicates a minimum bullet lead length of .8828", or .4942" less than that specified under the 1939 GermanProof Law. The net effect of this difference would be a slightly higher chamber pressure in barrels chambered according to American (SAAMI) dimensions.”

So Frank, how is that for “Can you please give us a FACTUAL account ashow the SAAMI chamber spec's came to be? Where (Were?) they perhaps based uponPaul Mausers design, or did they just "make them up".

BTW; Paul Mauser did not design the 8x57 as you and I said. He and those involved in adapting the 8x57JS cartridge to the M98 action simply made the chamber modifications to make the8x57JS safe to use in the M98. The SAAMI dimensions came about by “special committee” as mentioned above and they came up with their own concepts for commercial 8x57 chambers in the U.S.A. which is not to be confused (as you obviously have confused it) with what the 1939 German Proof Law or the German military dimensions for the 8x57JS chamber specified.

So to finish Frank, let me quote someone from another thread; “Can we have one thread without this childish BS please.”

Larry Gibson

[frnkeore]

This is not childish play, larry! It's called finding the facts!

If you had read with comprehension, my third paragraph, above, you would have seen that I had already addressed whether Paul Mauser had anything to do with the 8 x 57. The Gewehr Commision was responsible for it's design.

I did some research today and found that the leade of the 8 x 57, is indeed 35mm long and still in effect in Germany as of at least 2002.

What brought this up was your insistance that the 8 x 57 had a freebore in the throat. It does not! The angle of the leade has nothing to do with freebore. Yes, it does regarding the number of calibers to the length of it, it's actually 4 3/8 rather than the 2.72 that the SAAMI chamber has.

Now, did anyone learn anything from our discussion? I think they did.

Frank

[Larry Gibson]

Whatever you say Frank..........

Larry Gibson