The caliber is 300 H&H, built on a 1908 Brazilian Mauser. Not opened at the rear, front only. The loads are not hot, 155gr Palma match bullets in front of 72gr of a slow powder. Brass is W-W. Shoots half moa.

Today while shooting in our local Hunter's association comp, I get a head seperation. The bolt is a little sticky. I clear it by the time honoured method of loading a round into the chamber and extracting, thereby pulling out the bust case. After 5 seperations in a row I pull out of the comp because it is now impossible to insert the bolt, plus the other guys are a bit peeved with me taking up so much time clearing the gun.

I take it home and with some marking blue I see that the metal just behind the top and bottom lug recesses has pushed up ever so slightly and is binding the bolt. The metal must have come from somewhere and I am guessing the lugs are set back.

I used some fine lapping compound to remove the binding spot and the bolt now travels freely.

BUT

I am scared the headspace has altered. If the lugs have set back, I can just see this getting worse and worse. I can't trust the gun this way.

Can this be fixed, or is the action scrap? The barrel is a real shooter.

If I have to get a new action, what should I look out for?

Pete,

You have every right to be scared. If you've set the lugs back, get yourself some jelly cause it's toast. I would have been a bit concerned at the start with the action having been lengthened at the front, very likely resulting in a weakend right hand bolt lug mortise.

If this were fixable, which I would not consider for a second, the amount of work it would take to correct the lug set back problem, reheat treat the action and reset the headspace, would not justify the risk.

Glad you weren't hurt,

Malm

[ 09-06-2003, 23:39: Message edited by: G.Malmborg ]

Sounds like time for a new action and a .300 Win Mag reamer..

Your braver than me to have kept shooting it in its present condition..

Hope you get her straightened out.

Mike

Hello pete

Sorry for the 300 H&H , I have one done on a M 1909 Argentinean Mauser , shoot around 300 rounds through it and still don�t know if it�s a good Idea or not , if you want to keep the rifle I suggest to use a VZ action or a good pre war M98 ( WW II ) the steel are a bit improved , I made mine opening the front feeding ramp , as the bullets of a 300 H&H don�t need a square magazine as a .375 H&H I made a curved front magazine wall and remove enough ramp to feed properly , this allow to keep a good part of the ramp to support the lower lug .

Saludos

Daniel

1908 & 1909 actions were noted for being a bit "soft". My guess too, is that the lugs are set back.

Pull the barrel off and look inside is the best way to find out.

IF per chance, they are not set back, set the barel back a turn, rechamber, and get the headspace tight again, and cut a new throat too.

As Malm said, sounds like a good re-heat treat is in order as well as setting back the barrel and reaming it again.

[ 09-08-2003, 19:22: Message edited by: Brad ]

I suspect the receiver is too soft, and needs to be scrapped! Just the front-end lengthening is not the ONLY problem here!

Pete
Savage hit the nail on the head. Get rid of that action and save what you can off of it.

I just got a FAC catalog in the mail the other day, They had vz24's for $75.

I also now where 2 pre war vz24's are. The guy wants $125 a piece for them.
These babies are butter smooth.

With your bolt and trigger etc. this would be the only way to go I would think.

Good luck
Shawn

Hi guys,

I tracked down the supplier of the original action, they have expressed their sympathy and they will supply me with a nearly mint VZ24 receiver. I will salvage the bolt, Gentry safety and Timney plus the bottom metal. He can supply an FN receiver too, but he says they are a bit ratty and pitted.

He actually has lots of VZ24's I am thinking of stocking up on a couple of them.

Some of the engineering guys at work here say this kind of thing can be metalsprayed and hardened, but I don't think that kind of technology is appropriate for a nearly 100 year old rifle action - the metallurgy may be a problem.

Pete

Pete... love the "statistician" quote.

Our own Mark Twain once said; "There are liars, damn liars and statistician's."

Forgive my ignorance, but can you easily build a 300 H&H on a VZ-24 reciever?

Pete,
Having only built three of the long H&H on M98's, I found that milling the bolt stop and BACK of the action will keep you from cutting critical metal away from the front feed ramp, less than .045-.055" at the front maximum. It takes a lot of time and small carbide end mills, but it's a safer approach. Modifying the magazine was more time consuming than the action, due to the cutting and rewelding of additional sheet metal and finish work.

Anyway, what bothers me more on all the magnums is that the Forster GO guages are correctly made to SAAMI specs of 0.220" for the belted magnums.
However, I've measured over 100 different manufacture's cases and they were 0.215" at the longest...some were as short as 0.212".

This means that the case & bolt can get a 0.005-8" dynamic "running start" before the lugs catch in the action, assuming the case was fed all the way into the belt recess of the barrel or the firing pin knocks it forward. I do believe this repeated stretching can cause battering and receiver lug upsets of your type.

I'll stop rambling, but what I suggest is that when you headspace the 300 H&H barrel onto the VZ-24 action (or have it headspace), use a measured case (0.215" belt to head) to check GO and this will eliminate the .005-8" gap, or excessive headspace as some would call it.

Hotshot

Hotshot,

Good point, I am thinking tho' that if one were to necksize or partially size only then you are headspacing off the shoulder and not off the belt? Then you are treating the case as tho' it did not have a belt at all.

Thanks

pete

Hotshot,

Back about 1981, me and Mike Bellm sat down and measured a bunch of belted cases, and of the brass we had measured, found a dimensional difference from the forward edge of the belt and the case head of as much as .013. This probably did more to influence the way I set headspace on belted cases today, than anything...

Today when I set the headspace for a belted magnum, I will usually set it so that the bolt will not close on a "go" gauge. The folks who I do this for understand why, and will check the fit of each piece of brass be fore they load it. Those that fit stay, are fireformed and necksized, and those that don't are tossed into the scrap brass bin.

Malm

John Ricks started a thread here last winter that echo's Malm's comments.

Not to ruffle feathers as I am a traditionalist also but the .300 H&H is not that good a cartridge period. It's eight degree shoulder is just not enough to hold it back even if you make them out of 375 brass.

For those Mausers your way better off chambering for something like the a WSM, .308 Norma Mag, 7mm RM or .338 WM and not trying to make the action do something that it was not made to do. Mauser made magnum length actions for magnum cartridges. There is a reason for that.

I made my cases from 300 Weatherby just never headspace it on the belt I adjusted the sizing die to just touch the shoulder , no cases lost with head separations in a 300 firings and no more than 40 cases used ( lost a few by neck split ) , maybe the sloppy 8 degrees it's not what the new generation cartridges look like , but feeding it's absolutely perfect , my M98 even feed empty cases , and I love it .

Daniel

Pete - There are some battles that just aren't worth fighting. This sounds sort of like one of them. I don't know your situation and I'm no expert gunsmith...but my every instinct on this incident tells me not to go down that road again.

Rather than potentially put a bunch of time and money into a KNOWN PROBLEM, if it were me, I'd start over and change horses. I would build a new rifle with a new action. On the surface that may sound like the most expensive option, but in reality it may be the cheapest. There is such a thing as sending good money after bad.

Sounds to me like you are lucky you didn't have a catastrophic failure. Take care and good luck.

I made a bunch of rifles based on brand new 1908 DWM mausers and new 1935 Oberndorf mausers. The 1908s are a mild steel action and are relatively soft. I would prefer to stick with standard cartridges on these. The 1935s are among the best of the Mausers, to me, and I don't mind using them for anything.
I have made some H&H chambered rifles on mausers and had no problems but would no longer do it just because I've seen so many which were set back. On the bright side, these actions will set back but they seldom "grenade" like some of the harder actions.
I like the 1908 actions for a standard caliber but don't really like them for magnums. Regards, Bill.

.300 WM Better design, better brass for match shooting, better fit.

Mike

Not to beat a dead horse but page 86 fig 97 of the Kuhnhaeusen manual shows a 98 action that has been notched at the back of the ring and ramped forward to enable the action to feed .300 H7H cartridges.

It is scary thin on metal and just looks dangersome...

Mike

My personal preference is not to build magnums on militry mauser actions period. I've done it with no problems, but I've also seen even a VZ24 with set back action lugs on a .458 win conversion. Why bother when you can buy Rem 700's or M-70 win actions so cheaply? Unless your building a DGR keep the old mausers for sub 50KPSI cartridges.-Rob