I have an opportunity to buy a small ring Mauser action,with no bottom metal for $40.00.It has slight filing marks on top forward edge of the reciever ring. It is stamped Amberg 1911,the bolt is turned down (factory)and the bottom of the bolt handle is flat and checkerd.Is this action safe to build on? Will standard 98 bottom metal work on this action? Is it worth $40.00? It dose not seem to be sprong.

Paul K

Paul,
I don't know that model, (amberg 1911) what's the crest say?

quick way to verify that it's a 98 is to take the bolt out, and count the lugs... there should be two in front, 1 in back

no, 98 bottem metal will NOT fit, but mexican mauser or 96 will

jeffe

m98 bottom metal "might" fit. am not sure of the date of inception but germany had a model karibiner 98a and there was also a polish model that was an exact copy that was pure 98 in every respect except the diameter of the receiver ring. i had one of these i built a 25-06 on once. very nice, tidy actions. and my recollection is the bbl thds were likewise same as a 98. small ring doesn't automatically imply shorter. it depends on the purpose that action was originally built for as i didn't think the Kar98a's came along till up in the teens, sometime before the end of the war.

Small Ring? If so, it's probably a KAR98A. These were small ring rifles which used large ring barrels, and as such are not recommended for conversion to high intensity calibers. They are the same length as standard Mauser 98's, and use regular M98 bolts and bottom metal.

S40

if by high intensity what is meant is 270 winchester, etc class ctgs, the small ring in and of itself is not a problem. the karibiner 98a's and the polish version were both fired w/ the same 8x57S round as any other WWI or later german mauser. my 25-06 came out fine and i built a 22-250 on a (small ring) mexican 1910 w/ no problems. no telling how many 270's and similar were built on g33/40 actions and those are small ring even tho at a glance don't look like one because the sidewall is also thinner.

the typical concerns of "small ring" actions are the lack of a safety lug, lack of a gas deflecting flange and in most all cases metallurgy as relates to period of mfg as they're typically earlier than most 98's.

the radial and tangential stresses in firing can be and are carried by the barrel anyway (and for the typical barrel steel have a pretty high margin of safety). i.e. the barrel alone can carry that load. in fact, for the stresses in these 2 directions to be transferred to the rcvr ring the bbl thds would have to have an incredibly tight and perfect fit to the rcvr. the rcvr ring serves to hold the bolt to the breech. radial/tangential stresses on the rcvr ring itself really come into play in the event of a massive case head failure.

quote:

Originally posted by South40:
Small Ring? If so, it's probably a KAR98A. These were small ring rifles which used large ring barrels, and as such are not recommended for conversion to high intensity calibers. They are the same length as standard Mauser 98's, and use regular M98 bolts and bottom metal.

S40

date code (1911) makes that impossible to be a kar98 right?. the most common small ring action has the small ring barrel, and only one(that i know of) did a small ring action, large journel

this is why i said to make certain it's a 98, as the 96 could have dates into the 50s...

jeffe

Willmckee,
That is a broad statement.... There is not a better action than a small ring G33-40 or a 1935 Customs Guard rifle or for that matter a model 21 or 22 Brno which I think are small ring, but come to think of it I have not measured them in all the years I have used them....

jeffe,
have to distinguish between 2 things. the WWII standard german battle rifle was the Kar98K. there was a totally different animal dating from WWI era - Karibiner 98a. as such was a shorter barrel than the gewehr 98 and became essentially the pattern - so far as over all length - for the subsequent K98k. it may still have been impossible because i was thinking the Kar98a dated from 1917 or 1918. will have to check in Olsen for the date of adoption.

where it gets confusing is a) this is not a commonly encountered variant and b) both begin "Kar98". it's the subscript of "k" or "a" that distinguished so far as nomenclature.

snall rings - there is also the hva and carl gustaf actions but those are in a slightly different light as are later homogeneous - i.e. "modern steels" - metallurgy and are "probably" stronger.

just checked olsen; the carbine 98a (aka Kar98a) was adopted in 1908. distinguishing features "...small diameter receiver ring.." and (here's the punch line) "...peculiar turned down bolt handle with the knob flattened and knurled on the underside."

the german arsenal mark should pretty much nail the lid on that coffin. pat yourself on the back; you've got an outstanding action for building into a light weight sporter.

the 25-06 i did on the one i had, the shaw barrel was only abt .025" or so on the radius smaller than the rcvr ring itself. when bbld and in the stock it looked very sleek, almost as if rcvr and bbl were one continuous piece.

Gentleman:
Sorry for the delay in getting back with you. I checked the action today and it has a crown on the receiver ring,then Amberg then the date of 1911 under that. On the left side it says what I believe in fancy script KAR 98.It is a small ring for sure.It has a few proofs but I have no way of checking them for I loaned out my book of proofs a few years ago and do not think I will ever see it again.

Thank you
Paul K

To follow-up on my earlier post, the KAR98a is a small ring (1.3")action threaded to accept large ring (1.1")barrels. Doing so makes the front ring 0.12" thinner than it would be if threaded for a small ring (0.98)barrel. The thin ring is why some gunsmiths (including Kuhnhausen)recommend not chambering these recievers for high intensity rounds

Gentlemen:
I thank you all for your input.Your responses have been very informative and educational. It is nice to have a place to go to get help and information when in doubt.

Paul K

just for pure grins ran the stresses on the rcvr rings. some assumptions:
a) when i say "small ring" mean "small ring 98", not 93/4/5/6 models
b) assume atmospheric pressure = 0 to make the math easier (and rel to 55ksi it is; i've done both ways and the difference is a nit)
c) assume bbl and rcvr ring are a homogenous unit and stresses get 100% transferred thru this joint - they aren't and they won't but this gives conservatively high #'s
d) breech pressure acts over the head dia of the case (i see this noted erroneously all the time. the thrust load generated is the breech pressure times the maximum cross-sectional area INSIDE the case. yes, it's transferred to the bolt thru the base area of the case but this is simply NOT the area used for load calculation)
e) breech pressure is 55ksi. which is plenty. any more than that get a bigger case. is no sane reason to load 65-70ksi.

for 4 examples, large ring mauser w/ standard and belted heads and small ring mauser w/ each of same. total combined stresses for the above 4 ceg's come to 68,500psi 71,500psi 72,000psi and 75,600psi. in other words a standard ctg in the small ring is virtually identical to a belted mag in a large ring. and a belted mag in a large ring is only 6% greater than in a large ring.

have to confess have not read kuhnhausen's book. a buddy has it, said he's real big on re-heattreating mausers so i never bothered any further. i'm in agreement w/ ackley and lott on that point - don't do it. can't second guess 75+ year old metallurgy and heat treatment.

de haas was of similar opinion tho on conversions. said the germans thought nothing of using these actions for full pressure 8x57S loads (and 55ksi is 55ksi whether an 8x57 or 30-06 or 300mag) but he felt best to avoid them for belted magnums. fair enough as the action is ideal for a light sporter and who wants a light sporter in some big magnum caliber anyway.

I reckcon i was wrong on the date cycle!
jeffe

Just to clarify:

WWI era small ring 98's (Kar98) use a large ring barrel and have less steel surrounding the threads than any other 98 ever made.

WWI era 98 metalurgy was not as strong as that of the late '20s and '30s.

Military surplus actions in general are subject to more unknown use/abuse than commercial actions.

When you combine the above 3 issues, you can see why it is not recommended to use a Kar98 for any cartridge over the 8x57, and I would certainly not recommend investing too much money in such a project. I am aware that some folks have successfully chambered such actions for howitzer shells, but it is a roll of the dice.