Home Forums Hunting & Shooting Custom Rifles & Wildcats Mashburn Teaser

Allright from what I can gather (from my 3 minutes of research):

http://24hourcampfire.com/ubbthreads/ubbthreads.php/topics/5434483/1

I'd need 300 win mag cases to resize into 7mm mashburn cases. Looks like you can send them thru the RCBS full length sizing die and then fireform. You get about 150 fps over the 7mm rem mag in velocities. Does anyone have a drawing of the 7mm mashburn cartridge so I will have a better idea of what I'm looking at? Thanks guys....Oh by the way I don't like the 300 win mag but have tons of brass and maybe 1 rifle I may get rid of. Sounds like I may be killing more than 2 birds with one stone by going to the mashburn. Am I right??

K, you have so many rifles. I'm having a hard time believing you don't have a donor for a 7mm mashburn....See you shouldn't have bought so many 270's and called them donors.... ...I may have a good shooting ruger tang safety m77 that would make a great donor. It's a 300 winny though...It would make a great 308 Norma mag donor as well....Wait, maybe I should hang on to it...

The 300WM case is awesome when it's necked to .284...and actually has a neck.

Think how awesome that donor will be when those amaxs are running 3,100-3,200fps.

Here's the details on the case.

Thanks Jr, exactly what I was looking for. You're right, "3100-3200" with the A-max would be the chit....One heck of a long range rig....

Nah, man, build the Norma, then invite me over to try it out. I can find a 7 Mag 700 pretty easily.

And the excess rifles are probably going to have to go to fund the divorce...

jr: That rifle is a gonna be slick! And yes, it will do what everyone on here says it does,which is about 100-150 fps more with ny given bullet weight than the 7RM...however what I have noticed about the cartridge is that everyone who builds one seems to end up about the same place velocity wise with similar bullets.

Can't speak to 26" barrels as all I have worked with have 24".My last chrongraph session with it back in October had the 160Nosler Partition at 3180 and the 162 Amax at 3160,both with 75 gr of H1000.75.5 will put either bullet over 3200 fps.


bsa: That M70 will work just fine, and you can either leave the magazine as is and run your cartridges to 30/06 length, or swap out magazine parts for H&H and seat bullets longer if you want.Yes you can form cases with just the FL dies and Redding did this when we ordered the the dies from Redding...I am pretty sure that my dies and Bro's were the first set of Mashburn dies that Redding made;both our rifles used Dober's reamer.But this is a wildcat, and a guy will no doubt run into very minor tolerance differences rifle to rifle,and I find that I like forming cases using the Form/Trim die set from RCBS which works very well.I loked on Midway recently and they are available via special order.







Dober got another PM on a Mashburn build yesterday (from a poster everyone on here knows ) This guy is VERY knowledgeable,and had the spare parts for one hanging around...actions, barrels, everything....LOL! I won't say who it is ...he will tell his own story.

Can't tell how many guys have just taken a stock Rem 700 in 7RM and just run a reamer through them,and had at it.This is a very simple conversion that needs next to nothing other than rechambering.One fellow who used to post here,did a Rem conversion to Mashburn;he texted a pic of a desert big horn ram he killed with his last month.

Some say the Mashburn is not "worth it"...and I suppose they are right.If you want to be logical about it, I guess the same could be said about the 280AI..the Mashburn is at least as worthy as a conversion to 280AI,and if one is worthwhile, the other certainly is...

But if there is a "problem" with 175gr-180gr bullets at app.3050-3100fps,160's at 3150-3250fps,or 150's at almost 3300, I'm afraid I don't know what it is....I do know that since I built mine, my desire for another BG rifle has sort of fallen into a sink hole.

KDK: Time to sweep the safe,cull the herd, and step on the gas...

Dang... My 7 RM would look good in Mashburn.

Dober, you got extra dies?

Indeed it would....

Mashburn is the (old) new black.

I have an extra set that I use as a loaner set, you could use them till yours come in...

Plus my 700 will be heading to Dr Dan along with the reamer in a month or so. He could punch yours at the same time...

Dober

I saw the Dr. yesterday dropping off my 243 AI project, should have just given him my 7 too.

Next time you find some virgin 300 wm cases buy them. You'll be needing them...grin

Dober

moar teasin'

Muy bueno

Dober

Wow, that is a very fine rifle. It looks like it will be a blast to shoot. If you can get some H1000 you should try it with some 160 gr bullets and the 162 gr Hornady. My gun smith has my 7mm Mashburn, he is letting out the throat on it and is re chambering my custom stocked 700 Rem to 7mm Mashburn also. Good luck! Randy

The Hornady book shows loads for the 7 MM Roy of 76 grains RL-25 and H1000 with 175's at 3100. My latest Mashburn, a rechambered 7 Rem, works with both those loads. 175 Sierra with 75 gr. H1000 chronod at 3065. Lot's to like about that.

I'm hoping it likes the Barnes 168LRX (or the 145LRX or 150TTSX) since I'm in CA. Surely it will be fun to experiment with. I've got 2 rifles to develop loads for now, and a third (260) that I'm going to have built soon so I'll be pleading with the wife for range time.

Any idea what she weighs?

On the brass forming, I'd agree with Bob, the Form/Trim die set worked best for me. With the Form/Trim set, you neck down and bump the shoulder back in a two-step process instead of a one-step process as with the FL die. I tried forming with RCBS FL dies and it didn't work as well for me. Of course, that doesn't mean it won't work for you, but if it doesn't, the Form/Trim set would be the next thing to try.

jr: That's looking pretty slick!

Very nice rifle. Digging that all black look. Some 140gr TTSX bullets at warp 9 would just not be fair to anything with fur.