7mm Mashburn Super Magnum

[longrangehunter]

That would have put a smile on Bob Hagel's face, looks like you have yourself a great load.

I hope so, I have been wanting a Mashburn since I was about 14... Took a couple of years to make it happen..

You and me both little buddy, but I'm sure it wasn't until a few years later in life for me. My good friend Mark gave me his book Game Loads and Practical Ballistics for the American Hunter and read that more then any book I ever but in my hand.

Living the dream with that in your hand and nothing ever really needed for the vast majority of our hunting needs.....

 

[efw]

The more I read here the more I think that 03-A3 may have to go Mashy...

 

[SJB358]

The more I read here the more I think that 03-A3 may have to go Mashy...

Not trying to sway you at all Eric. I don't particularly wanna try to tell you its the bottom line for 7mm's, but it is an easy cartridge to work with and seems very well balanced. To me, it's sorta what the 7mm Rem Mag should/could/wanted to be.. :grin:

If you go into it with expectations of a 160 at 3200, 175's at 3050, you won't be let down, and all from a 24" barrel.. It's really hard to not like. Even the fireforming loads I use are pretty accurate. 140's at 3200 is top end for a 280 Ackley, but really just easy stuff for the MSM. I believe Art Mashburn got it right back in the day. You can go bigger for more powder usage and a little more speed, but the MSM has been very easy to shoot as is.

 

[efw]

That sounds awesome. I think I am going to get my Win M70 (now 280 AI) a Douglas 6-06 barrel so I'll end up w/ a 7x57 & 7 MSM.

What do you think you can get speed-wise from a 145 gr LRX?

 

[SJB358]

That sounds awesome. I think I am going to get my Win M70 (now 280 AI) a Douglas 6-06 barrel so I'll end up w/ a 7x57 & 7 MSM.

What do you think you can get speed-wise from a 145 gr LRX?

I'd bet you'd be in the mid 3300's or better Eric. I don't have much experience with Barnes anymore but that'd be a safe estimation.

I get 3200 or so with the 139 Hornady, 140 BT and AB with the fireform loads. So it wouldn't be tough to get more with a case of slower powder.

 

[jimbires]

man it's nice when things work out . it's shooting everything pretty darned good . I agree , play with the seating depth a little .

I'd have to look back in my notes to be sure . I think I was getting 3100 FPS with a 160 TSX in my 7 rem mag from a 24"bbl . I'd say 3300's is a good guess for the 145LRX in the MSM

 

[SJB358]

Thank's Jim. It did turn out real nice, at least my sorta nice. I know the rifle will pack well over hill and dale, and should work real well for elk up on the mountain.

 

[SJB358]

Shot the 7mm MSM at 200 yards today to see what the 160 AB's were doing. Pretty happy with it overall, considering the rifle wears a 6x42. Really looking forward to getting it out longer..



Still working with the 175 PT's. Those are getting mighty close to being great, just need a little more time to work with them.

 

[elkeater2]

This is a fun read, Scotty. I have a couple setups that group like that and like them. My present group of friends and critics would ask if the scope was loose - great vertical, but I wished the horizontal was as good. I think it's harmonics myself, and you'll find changes with seating depth. Since the wind blows out here now and then, I have another excuse built in
EE2

 

[zacii]

How does the 7 Mashburn compare to the 7 LRM that the Gunwerks guys tout?

 

[IdahoCTD]

The LRM is marginally better than a 7RM. The Mashburn and 7-300wm are 100+fps faster. Gunwerks pushed the shoulder too far back and lost too much capacity.

 

[preacher]

I still have Bob Hagel's book on game rifles I got back in the early 80's and somewhere there is an older book with Warren Page and his 7 MSM. I was impressed. I didn't have a chrono then ( I didn't have much of anything then, ha) and my wife had given me a Mod 700 7 Rem Mag. I tried to get 3100 with the 160, but all I could safely get with IMR 4350 was 2950 ( I shot it over a chrono a guy had at the gun range) I was so disappointed. I wrote Bob Hagel and asked him about having my Mod 700 reamed out to either the 7 MSM or 7mm/300Wby. He wrote me back ( I have the letter somewhere!) and said the 7MSM would be the best but the 7mm/300Wby wouldn't be worth it with a 24" barrel. Since I lived in podunkville Tx then and had a young family, I dropped the idea. Later in life, much later, I "scratched that 7 MSM itch" for speed with another 24" 7 Rem mag but with the Barnes 120X, then went through a couple of 7mm STWs and last a 7 RUM. I had sold my 7 RUM to help pay some bills for my dear old mother and when I went to replace it, good luck finding brass/ammo! I decided to go retro and try a 7mm Rem Mag again, this time with a 26" barrel with R22, R26 and R33. I would be happy to get 3100 with 160 and 3000 with the 175, of course, more is better! ha. I just have to get some time to shoot again! I am pretty sure I can outright buy my smith's Mod 700 in 7mm/300Wby, so I kind of have my greedy beady eyes on it, ha.

 

[SJB358]

I read the same Hagel books Jim. That's probably 90% why I did this rifle up. Mine easily runs 3200 with 160 ABs and PTs with H1000. There's more there with Retumbo but accuracy is excellent. I'm getting about 3075 with the 175 PT. Overall, I couldn't be more pleased.

 

[SJB358]

Did some more work with the 175 PT's yesterday. Seems the further I seat them the better they are responding. Going to keep pushing them in, but I am pretty happy to see it so responsive.

 

[DrMike]

These are 200 yard targets, Scotty? Promising, always more promising. That is a cartridge that deserved far more attention than it received when first created.

 

[SJB358]

Those are 100 yard targets Mike. I haven't stretched it out real far just yet. Shot it a few times with the 160 AB load at 200. Did real well in my opinion. The 175 PT's are taking just a touch more work than the 160's did, but they are coming around.

I agree about the cartridge. It seems to make velocity pretty easily, the cases are holding up really well. I am getting an easy 3050 from the case with the 175 PT and H1000. Can't find much to not like about it. All from a 24" barrel makes it feel pretty handy.

 

[DrMike]

That punch would be adequate for anything on the North American continent. Good stuff.

 

[SJB358]

Well, I think I got it done with the 175 PT. Final load is Hornady cases, CCI250's, 73.5 grains of H1000 and the 175 PT at 3.460 COAL. Seems like it wants to shoot right there. I can't see monkeying around with it too much more. Plus, with just a FX3 6X scope, it's not meant to be a rockchuck rifle..



I'll check the speeds again shortly, but I am in between 3050-3075.. I am going to try some 175 Sierra GK's for a practice sorta bullet soon, but I am happy the rifle is ready to elk hunt now! :twisted:

 

[JD338]

Agree. That load is a keeper.

JD338

 

[Leslil]

That looks great.
I'm going to work with that 150 and R22 load for now. Then I have 2# Retumbo and 300 168gr. Custom Comp seconds to play with.