7MM Mashburn Short Mag?

lowmaster

I have I rifle I believe was built by Art Mashburn. It is 7MM but the cartridge is not marked any where on the rifle. I made a chamber cast and have come up with some dimensions
Case length is 2.500
Case head to body/shoulder junction 1.910"
30* shoulder
Dia. at body/ shoulder junction .496"
Based on a belted mag .532" dia case
I have found dimensions for a Mahburn super and a Mashburn Magnum but not for a Mashburn Short Mag I have seen some reference to a Short at 2.480" and at 2.530" but cant find any dimension to confirm . My goal is to identify the chambering of the rifle and mark it accordingly I would also like to source a die set and load some ammo to shoot the rifle.
I appreciate any help that can be provided
I can post pics of the rifle or of a cartridge if that will help

MIKE WISKEY

P.O. Ackley's book (vol. 1) has loading data but no dimensions.

lowmaster

I did turn up Ackleys reference 2.530" length IIRC. This is certainly a tough nut to crack. I hope somebody familiar with Mashburn will chime in with some insight. I found through my research that Mashburn made his own tooling so there is not much info at reamer manufactures as far as reamer prints go

lowmaster

I have not gone that route might be an avenue to try. I have some feelers out to a smith in the OKC area he was going to check with some people in the area This thing is becoming my white whale.
Here is a pic of the rifle and a pic of the cartridge compared to a 7mm rem mag The rem Mag is on the right

charliemeyer007

Nice looking rifle. RCBS did make custom dies based on cases (3) fired in your rifle, expensive but exact.

I would just neck size with like a 7mm Rem mag die, perhaps a collet type. Cast lead bullets with light loads are what I use for fire forming.

I once had a Springfield in 300 Gibbs. A 30-06 with the shoulder moved forward. I opened the case mouth to 8mm, then carefully sized the neck back down until they fit. Used Unique and a cast bullet to fire for them. After that I just necked sized. Was in the top 10 of the most accurate rifles I ever shot.

added Have you considered opening it up to a standard cartridge like perhaps a 7mm STW. BTW how does the bore look? Especially the throat zone?

Tflogger

My first thought was the 7/338 magnum.
close but now cigar.

Ambrose

I don't know if anybody remembers the gun writer Warren Page anymore. He was very involved in the early bench rest game. He hunted with a 7mm Mashburn Magnum. His writings are still around and maybe that might be a source of information.

lowmaster

Ambrose thanks for the reply I have found references to Warren page and Bob Hagel on the net with regard to the 7mm mashburn. Unfortunately the cartridge was the 7mm mashburn or 7mm mashburn super both of these are larger than the version I have. I thought I was on the right track there but the trail went cold

mrmike08075

Wildcat cartridge platform ownership can be a labor of love...

I have a .270 Gibbs (FN commercial action) and a .14 Donaldson wasp (Remington model 700 action)

I was lucky with the Gibbs - it was actually built by Rocky Gibbs and correctly marked and still had the dies and reloading equipment and extensive load data and correspondence between GIBBS and the original owner (from which I had superior ammunition load up a variety of ammo including tube based front ignition compression loads - had the brass made by Mike at grayback wildcats)...

The .14 Donaldson wasp was custom made in the early 1990's and the owner had some personal load data and it came with the dies and 500 unused fire formed cartridges...

I sent copies of the Gibbs load data and correspondence to Ken Ramage when when was running cartridges of the world - also let superior and grayback have copies so they would survive and could be available for others in the future...

I also posted some of the data here and on other boards.

You must understand that your platform may be a unicorn or an orphan - it's possible there are less than 10 examples that were ever made - you may have to do chamber casts and have brass and dies custom made...

I would suggest that you have anything you make or have built be labeled and or stamped to indicate the caliber - wildcat status so the legacy survives going forward...

When and if you do work up load data or have it done by one of the experts or companies you compile all the info and disseminate it on a few boards - contact COW and whomever is editing it now and pass on the data to them and see if they will publish it so it will survive and others may find it in the future...

I assume that like in my case the proprietors and creators and original patrons - owners are deceased and cannot be questioned or provide assistance...

You now have quite an involved project - an incomplete legacy - I hope your research yields more results but I suspect that you will have to advance things yourself - we would all like to see the results or follow the process...

The 2 companies I mentioned may be of some help to you - I am not an expert - others here are far better qualified - good luck.

Mike

lowmaster

MR Mike my objective is to label the rifle and get some dies so someone does not have this issue down the road. I would like to tie this rifle to Art Mashburn if I can. If I can find a Mashburn cartridge that is the same as my chamber that would help me tie the rifle to him. I am fairly certain he built it and the dimensions of my chamber mirror some of the design characteristics of the bigger Mashburn Magnums. There was a thread on this forum a while ago that mentioned a mashburn short magnum but I cant find it now I will search some more.