Does anyone know a 'smith that has a 7 mashburn reamer that can clean up a 7 RM chamber on a 700?

PTG doesn't list it on their reamer list, yet I've seen where they have been PTG 7 mashburn reamers sold in the past. Do they have a reamer print for it and you just need to call them?

GG I am pretty sure Gene Simillion has a reamer.

Also PM Dave7mm on here. I think his smith has a reamer but don't know the smith myself.

The place that rents reamers (and thier name escapes me right now) has one as well as the nearly identical 7mm/300 WinMag.

PS GREAT idea and caliber choice!

Any idea on PTG though, do they make one?

I believe PTG has made a few

I remember now the name of the place that rents reamers. They are called 4D gunsmithing supplies and they rent out Reamers and other gunsmithing tools that a 'smith would only need from time to time.

A number of years ago I rented a 300WBY reamer and a T-handle for it and re did a Browning A-Bolt chamber from 300 WinMag to 300WBY Magnum which turned out wonderful. Beginners luck I am sure but with care and lots of cutting oil it can be done and they will help you by renting you the tools to try it yourself if you want to. If you mess it up, you have only screwed up a factory Model 700 barrel and those plus aftermarket specimens are easy to come by.

Best of luck whichever way you go.

One more option. I have a Hugh Henriksen reamer that was used to do one chamber that I will put in your mailbox for $150.

Buy your reamer then sell it. Have the smith cut a Wilson seating die with the same reamer.

Bull's-eye

Yep, a rented reamer may have done a bunch of barrels before you get it. Even if re sharpened not as good as a fresh one IMO. And, you can probably re sell it after use for about what you paid. The 7 Mashburn Super is a fairly popular wildcat with easy to make brass and a significant performance improvement over the two other more common 7mm Magnums.

Would really like to purchase my own reamer. Not ready to buy yet, just gathering info right now.

Not really sure which way I'm going on dies yet. Are the 7mm Mashburn Super Magnum Short dies that RCBS makes the right ones? Not sure what short means? Was thinking about buying die blanks and having them reamed out. Would I need a separate reamer for that?

This is my reamer from PT&G, I'm sure the numbers at the bottom right should be able to help them.

GG: Yes that's the one. There is some confusion in the name but that's what RCBS calls it for some reason.

Art Mashburn actually did 3 7mm wildcats on the H&H case; one was intended for 06 OAL like a 7 Rem Mag, the other on the full length H&H case (like the STW),and the 3rd, more notorious one we are talking about here, the 7mm Mashburn Super, which was intermediate in case length.

Your Rem 700 is an easy conversion and should require nothing more than a rechamber. I know a few people who have done it that way.

I notice you're from Maine....too bad we didn't know. You coulda swung by The Forks and seen mine. I had it up there in November.

Kevin Weaver, Weaver Rifles, Payton CO.

PS...just build (ream) it, you won't regret it.

JR that turned out nice!

That looks like a fantastic rifle.

I have a 24" on my 7 RM currently, but I also have a brand new 26" 7 RM take off as well. When I get ready to do this, I think I'll have both barrels set up at the same time. Really looking forward to seeing what this can do. I'm currently trying to create a Quickload file for the Mashburn off of some reamer prints I've found online.

Bob, that's too bad. I'm actually down near Bangor.

GG: Mmm...Bangor wasn't that far

All barrels I am familiar with have been 24" IIRC. Not sure what a 26" will do but I bet it won't be bad at all!

Bob which do you feel is a better method of making the brass; form/trim dies and then fire forming or, just running it through the FL die and then fire forming?

Also any neck turning needed at all?

How is case life once they have been formed? Assuming you don't step on it too hard.

I appreciate it.

Not Bob.
Just run 300 Win mag brass in a FL die.
Skip the trimming.
No neck turning required. Depending on the reamer of course.
Case life is excellent.

dave

00

3700fps with a 120gr Barnes TTSX out of my 26 inch tube. Will begin playing with some 139's and 140's when I am feeling a bit better. Looking forward to the experiments and shooting.

That is how I make my brass as well. Piece o cake.

Dave Kiff will make just about anything you can dream up..or he used to anyway

GG: Dave and Safariman are right. It can be done with just FL dies.In fact the first dies Redding made for the Mashburn were formed with brass from my rifle for dimensions. They thought only FL dies are needed.

I use the F/T dies, because I already have them but have done it both ways. Either method works.

I was and am too cheap and broke to buy a set of 7mm Mashburn dies, but my rifle will eat up and fire just fine 300 WinMag brass run through a 7mm STW FL sizing die. From that first form down, I merely run that same die back a few turns and neck size only.

The 7mm RemMag to 7mm Mashburn Super conversion is SO easy, and makes SO much sense, I hope and think that we will be seeing this done to more and more vanilla 7 Mags.

If anyone has any experience or data for the 7 Mashy or the nearly identical 7 practical and 7mm/300 WinMag with 120-140gr bullets pushed fast, I would love to see it. H4831 got my Barnes 120's to 3700fps but I have done precious little testing or development other than toss together that quick load for a soon upon me deer season and call it good enough. My hope is to get the higher BC 139-140's out the snout at 3500fps, (from my 26 inch octagon barrel) safely and with good primer pocket life.

Is this something like what your looking for?

Looks like it shoots pretty good JR:-)

I'm the weakest link in the chain, someone really knew what they were doing when they put it together.

Can a Ruger 77 MK 2 action in 7 MM Rem Mag be Rechambered to the Masburn the action mag length is not as long as a Rem as I recall. Or will mag length be to short?

Are you looking to part with your dies?

kk: With the caveat that I haven't done it, if a 300 Win Mag fits an action, a Mashburn should. Bullet seating will be deeper.This will bug some people and others not at all.

Since I use M70's,and others Rem 700's it makes sense to use as much action length as you have, which is why my M70 has a 3.6" box.

Took the words right off of my keyboard

I think a Model 77 in 7mm Mashburn Super would make a fine hunting rifle. If the rifle is already one of the various belted magnum chamberings, should be a really easy switch to make.

safariman: I think so...

No Sir. I'm just in the process of putting this one together. Stock should be here in a month and I'm hoping the barrel is here by early spring.

Les! You are doing this all BACKWARDS, man! We rifle looneys are suposed to find some obsolete dies or bullets or brass etc. FIRST.... and THEN build the rifle around our great find!

Thanks for all the info guys, I really appreciate it. Should be starting my build in January.

Thinking an Edge ADL, bolt fluted/hollowed by Kampfeld, Talley LW's, and a 3.5-10 vx-3 with M1 ele.

Then sending it to Mr. Fosnaugh for Cerakote.

GG: But I thought there was nothing but short shots up there in Maine...

I'm thinking west in the future for hunts. I'm still young (20), got lots of life to live yet. But my heart will always be in Maine, and I'll always be here. My 375 H&H and Guide Gun got me covered for Maine pretty handily.

You can thank Beretzs for leading me to the Mashburn. I was thinking LRM, but then saw the light of day.

I went the lrm route and later regretted it. Had lots of pressure issues and brass issues and it never consistantly shot well. It also didn't seem to have anymore capacity than a standard 7 rem. It looked like a good idea and works well for some but I wish I would have spent the money on a mashburn. I just got sucked in by the beltless lrm.

Bb

You'll hunt the west It's great,all of it.

One thing you'll find......if you can hunt and kill whitetail bucks in Maine, you can kill deer anywhere on the Continent.

Scotty seems to like the idea of the Mashburn.




BB: I have never owned the LRM, but I have owned the Dakota, which is similar and a great cartridge,but gave me brass issues I never saw before. The Dakota made me spooky on the brass issue;I'd rather make my own from good old WW 300 Win Mag brass.


I think the beltless thing is a non issue.

Matt, let's hear the update on yours...

I know you've got some pieces ready to be put together!

All the parts are here...just need to call Mr. Fosnaugh and send it all out.

Specs will be:

700 blueprinted up nicely. .250" lug pinned

Rock #3 8.5 twist that will have a 3/4" shank and finished at 24".

McMillan Hunters Edge olive with black specks. Standard BDL bottom metal. Pillared and glassed, free floated.

All metal coated Cerakote Graphite Black.

Talley LW's holding a VX3 3.5-10 with an M1 ele knob on top.


Should have all the parts out the end of this week.

I've got 500 162 amaxs, 220 160 Bitteroot Bonded Cores, and 7 pounds of H1000 waiting on hand.

GG it sounds like you have it moving along very well. I'm very pleased with both of my rifles. Randy

Beretz your rifle turned out great. I really like it and great velocities that you are getting. What is the OAL that you are using with the 175 gr Nosler bullet? I need to work with the seating depth with it in my 700 Custom. Thanks Randy

Seen GG's stock. Very nice project coming together.

Here is where I am at so far with the 175 PT's. Hornady cases, CCI250's, and 73 grains of H1000.







As I seat them deeper, they keep getting tighter. It'll be a few weeks till I can get back out again, but 3.460, 3.450 and 3.440 will get run the next time out. I am running right around 3050-3060 with the load.

It has been a great rifle to work with. Responds well in all aspects.

Mmm...Scotty I will get to the range this week and shoot some 175's. Been awhile and I forget how they group!

Yeah, I am liking what I am seeing so far Bob. Hoping the 175 PT's track with the 175 BBC's..

Tried the AB's with the 160 BBC's again this past weekend. No joy. SO, if I wanna shoot the 160's, I'll probably have to work a little with the 160 PT's and see if I can get them to come together.

Been wanting to try some 175 grain partitions or 180 grain scenars but my load with 150 grain ballistic tips shoots so good I don't know if I will mess with it.

I am the same way with the 160 AB's Laker. They shoot really well in my rifle, but I have a decent stash of 160 and 175 BBC's I'd like to hunt with.

So, if the bottom falls out and I have no time to do anymore shooting, I have a great load.

I do like shooting this rifle though. Been a very pleasant experience.

Laker: Why bother? Got your load....run with it.

You'll want to try the scenars..

Rosco have you tried them on game yet?

Yes, thumbs up.

They can be destructive tho.

So not an elk bullet?

There's no elk I wouldn't run a 180 Scenar into out of Mashburn... They've crushed everything I've seen shot with them.

Tanner

That's what I like to hear. May just have to try them out.

If someone would send me some I'd be more than willing to give them a try. Oh, I'll need a elk to try it out on also.
I'm hoping to have mine in my hands by next Friday.

Laker, only seen two 7mm scenar'd elk so far, havent seen a recovered bullet yet..

What kinda twist do you need to get the Scenars to stabilize? Mines sorta slow since it's a Win factory barrel, 1-9.25/9.5 to the best of my measuring ability.

Laker, what is your load with the 150 BT's?

72 grains of IMR7828 for the 150s

beretzs: I've got a 1/9 on my 7 rem mag and the 180s shoot pretty dang well in that. All that has been over 4000' elevation though.

What's the real difference between the 7 Mashburn and a 300 WM necked down to 284 ( 284 Jarrett ) besides a slightly longer neck on the Mashburn. Does the Mashburn have more powder capacity too ?

Roy I don't really know....never measured the capacity of the 300 WM necked down. The Mashburn has slightly less taper. Six of one/half dozen of the other I think.

I think a lot depends where you seat bullets but we can bet any difference is pretty fractional. Whether he realized it or not,what Jarrett did is reincarnate the Mashurn in a slightly different form. But that's true of a few other 7mm magnums as well.

The mashburn has more panache

The 300/7mm RemMag has almost no taper, and the longer body and shorter neck so a bit more powder capacity. The plain 300WM/7mm is also reffered to as the 7mm Practical.

My 7mm Mashburn marked custom rifle is, I learned when starting to shoot it and inspecting the cases, actually a 7mm Practical. I can run a 300WM case into a 7mm neck sizing dies and have perfect brass. That is one of the things about buying someone else's already built custom, no way to really know the chamber dimensions until shooting it and measureing the fired cases or doing a chamber cast. I am OK with my slightly larger chamber and easier to form cases, and the beautiful engraving of the 7mm Mashburn is so pretty (on a tapered octagon barrel) I am going to leave it as it.

Safariman: "A rose by any other name........"

There ya go!


BTW, anyone have any recipes for 120-140gr bullets in a Mashy or a 7/300? I am still addicted to speed, though have some 140gr Accubombs to try as my higher BC possibility. Cannot wrap my head around barely over 3,000fps for my long range deersmacker, yet.

Thank you. That sounds like a mule deer nightmare!

Unless you limit shots to relatively close, a higher BC bullet started way slower will surpass your impact velocity upon impact.

But it would go against your machoism I know.

Your Mashburn should get a 140 over 3k with it's 26" barrel.

Hell the 7mm-08 can damn near do it with book loads and a 24" barrel.

My .280 A.I. shoots them at 3295 fps from a 24" PacNor 3 groove and a book load.

Buddies 7 RM and a 26" barrel clocks them at 3380 IIRC.

Dober turned me onto the 150s and IMR 7828. He uses them for all that walks. Im planning to run them in my limited entry bull elk this fall unless I decide to carry my kimber Montana in 7mm saum or 6.5mm saum depending on which one I decide to build.

You not interested in the 7mm WSM?

I've always like the 7mm saum. Seems like a 280 ackley in a short action and that to me is a good place to be. Nothing against the wsm just doesn't turn my crank

Stick with the 7's. Hard to find a better place to be.

I was talking about the real heavies of 160 and up.

I was (am) getting 3650 with 120's so figured I should not have to lose down to much lower that 3450-3550, which is still pretty darned fast and those will outrun my 120TTSXS pretty quickly, too.

But as for over 140grs, I still love mega speed bangflops on normal range Mule Deer fairly often, and the longer mid range trajectory. The other limiting factor is this... My beautiful Len Brownell custom rifle has an exquisitely sculpted and fitted checkered STEEL buttplate! Cannot get really pumped up about shooting the heavies with this rifle. And for deer out to 600 max I do not need to. If I need to shoot heavy bullets my 338/8mm RemMAg pushes 225-300gr bullets to some wicked velocities and has a nice, big soft Limbsaver recoil pad

I think that I will start with Dobers 150gr load for my 140's and go from there.

Safariman Id start with 7mm weatherby data and go from there for working up loads in your mashburn with 140s

That is how I ended up with the 120gr load I have, but of course the Mashburn (7mm/300 WinMag aka 7mm Practical in my case) outruns the WBY by a bunch at the end of the load development phase. I think that the case capacity on the 7/300WinMag is not far off from a 7mmSTW, so starting loads for that round might be an OK beginning place, too.

With the 4350 140gr. fire form load that it seams everyone uses, are they using mag primers or standard LR primers?
I loaded up 10 rounds the other day and after the fact I realized I used WLR. I know they will go bang I was just wondering from a accuracy stand point.

Les they will go bang and you will be fine.Never used them for the FF load (use Fed 215),but the WLR primer is no wimp.

The FF load does not shoot quite as "tight"for me in my rifle,as full house Mashburn,and it's slower than what the cartridge will do with a 139/140 but it's fine.Could hunt with it pretty easily.The 139 with 65 IMR4350 does 3150-3190 in my rifle.

I have only shot the 139 Hornady but Beretz used the 140 AB for app. 3200 with his FF load.

Thanks Bob.
I am hoping it tales a liking to a bunch of H1000 and a 150gr. Partition.

H1000 works with the 160's and 175's. That I know. Don't see that it should not work well with 150's too.

But you know how rifles are......

Les don't overlook imr7828 for the 150s

I have a jug of 7828, Retumbo, R22, and all varietys of 4831. 120 TTSX,120 BT, 150 PT, and 162 Amax. Keep the info flying.
And thank you all. I haven't even piped a primer in this rifle and I'm already loving it.

Les other than the FF load, I have not fed mine any bullet lighter than the 160's.

Seems the other guys will know about the lighter bullets.

Other than fireforming loads all I've ran is 150 grain ballistic tips and 160 grain accubonds both loads with IMR 7828. H1000 shot faster with 150s but wasn't as accurate as 7828

Me too. This combo works great in my 280's.

I have been working with H1000 primarily in mine. Does very well with both 160's and 175's. Retumbo would work just as well in mine but I didn't really have enough to work with. I get about 3050 from H1000 and 175 PTs, 3200 with 160's. Retumbo seems like it get another 50 FPS on those numbers.

Nice thing with the 7mm MSM is even those bulky powders like H1000 and Retumbo have PLENTY of room in the case to make it work well.

The 150 and 7828 sound pretty good.

140 AB and 65 grains of IMR4350 run 3225 from my fireforming loads. Around MOA. Could easily work with them, but heck, the accuracy on them is plenty for now and the speed is like a 280 Ackley +...

I have used RL-25 for my 160 gr. loads with fine accuracy +/- .5 in and 3275 fps. velocity. My 175 gr. load is 74 H1000 for 3075. I have some RL-33 to try with 175's but haven't had time to play at the range.

YMMV