Nearing the end of my 338 RUM build.

Mike Matteson

Well-Known Member
Joined
Jun 26, 2017
Messages
951
1. I am wondering how that was overlooked by gunsmith?
2. I feel that somebody will come up with away the fix the problem.
3. I wouldn't use the rifle until it has been solved.
4. It might be solved by getting 378 Wby Mag cases and sizing down to to the dimensions of the case to fit the 270 Wby Mag case. The 378 is longer than the 270 case to the shoulder. I feel that would work by sizing down a 30-378 to your 270Wby Mag.
5. I would wait until some of the others that have far more experience than me look at it. I have a 308 Norma Mag, and use 300 WM cases and size down the length of the case at the shoulder. I do have to trim the neck for overall case length.
6. You can get a different reamer for your barrel, and re-chamber the barrel. You would have a new wildcatter round maybe.
7. That sucks!
 

WildBillG

Well-Known Member
Joined
Sep 5, 2018
Messages
626
Location
Alberta
The barrel on the donor action was stamped 270Wby. What I think happened is the guy I traded actions with was messing around with a bunch of Mk V actions. When I got a hold of him he through an action with a cut down barrel but never checked things close enough. The only difference between the 270 bolt and a 378 bolt is the amount cut out of the face. Easy enough to over look if you had a bunch of bolts lying on a counter. Both the gun smith and I assumed the bolt was a typical H&H bolt face. In fact I fired 8 rounds before I had a case not fly out when the bolt was opened. My first thought was did some thing happen to the extracter.
 

Mike Matteson

Well-Known Member
Joined
Jun 26, 2017
Messages
951
Used rifles you don't know anything about unless you personally know the person that had it built or purchased. You don't know what chamber is like unless bore scope to look at it. Me I would have to have somebody look and tell me. I know that Wby generally have a lot of free bore in them. A lot of the time people are selling the rifle because they can't get to group. Somebody has a lot of rifles do get tired of them and want something else and wife is looking over his shoulder.
I am wondering if you can go back and get the correct bolt for it. You will still need to have it check out by a gunsmith.
The other is a 378 at the belt is .604 and 270Wby is .531. That .063 difference and at the belt. I would think the changes from a fired case and unfired case would have been noticeable. I am wondering why somebody hasn't come in and write about it.
 

WildBillG

Well-Known Member
Joined
Sep 5, 2018
Messages
626
Location
Alberta
Mike the gun has a brand new 338 RUM barrel on it now. The problem was niether me nor the gun smith ever thought to check the bolt face. Instead of a .532 or4 bolt face it is .580. The gun shoots ggreat it is just that some times it will not fully etract the case.
 

Mike Matteson

Well-Known Member
Joined
Jun 26, 2017
Messages
951
Okay I guess I didn't fully understand, because it got to 270wby mag. Now I got it. I saw the problem in ejecting the case. That could be a problem when hunting, and not ejecting the case and needing a second follow up shot, and that happens sometimes.
Well keep us posted. I have a 338 Win Mag in a Mark 11 Ruger with a 24" barrel. Using Win 760 powder @ 75.5 grs, Fed 210 primers, and Nosler 200gr AccuBond. It chronographs at 3230fps. It flatten the primers, but no creating. Now for extreme heat with the powder I am not sure on yet. This load was develop in hotter weather 20 yrs + back. Never did check to see how it work in colder weather. I hoping to check that out this summer, back in Montana, and winter to see how it does for velocity changes if any. Working on having a 338WM in 26" barrel built to see what it will do. I am a fan of longer barrels, and heavier barrels.
 

waspocrew

Well-Known Member
Joined
Mar 16, 2014
Messages
1,072
Bummer about the bolt face diameter not being correct. How long ago did you purchase? Probably a long shot trying to get the correct bolt at this point.

I have no idea how much a new Mk V bolt would cost, but my bet is it’s not cheap. If this were my rifle, I’d want the correct bolt face, so I’d either find a new bolt or rechamber to 338 Lapua, 338 Norma, etc. to utilize the bolt face you current have.
 

WildBillG

Well-Known Member
Joined
Sep 5, 2018
Messages
626
Location
Alberta
Waspocrew the idea of rechambering went through my mind but I really don't want to spend the money on new brass. 338 Norma brass is through the roof up here and that would be my next choice for a rifle. The guy I got the action off of had another add up this mourning maybe I will see he might have the right bolt sitting around.
 

WildBillG

Well-Known Member
Joined
Sep 5, 2018
Messages
626
Location
Alberta
I contacted the guy I got it from yesterday. He said the way I got it was the way he picked it up at the gun show. The gun smithsaid a guy might be able to get a longer extractor.
 

Mike Matteson

Well-Known Member
Joined
Jun 26, 2017
Messages
951
I contacted the guy I got it from yesterday. He said the way I got it was the way he picked it up at the gun show. The gun smithsaid a guy might be able to get a longer extractor.
I kind of wonder about that. Not knowing I didn't want to suggest that. I am not a gunsmith by any means, and want add that to the mix. I do think it would by worth while to check in that. Hopefully I learn something here, and you get the problem straighten out.
 

Primary

LRH Assistant
Here are some related products that LRH members are talking about. Clicking on a product will take you to LRH’s partner, Primary, where you can find links to LRH discussions about these products.

 
 

Recent Posts

Top