Home Forums Hunting & Shooting Custom Rifles & Wildcats The 7mm Mizzum

I have a brake on my 6.5x47 1000 yard bench gun.
Like it alot.
Just dont care for the bitch slapping on a carry rifle..
dave

I shoot a 7 lb 4 0z Sako A7 in 300 WSM.

It's accuracy load is a Barnes 175 LRX and 64 grains of RL17 for just a hair under 3,100.

This load in a light recoiling light rifle matches up pretty good to the Mizzum shooting 175 Partitons.

Their bullet BC's and velocity are the same.
64 grain load in the Wizzum might have less recoil.
The LRX performs like a BBC from my test in dry print if that means anything and penetrates as well if not better than a Partition.

Wizzum vs Mizzum.....pretty close.

Those two would be pretty close.

One reason I have a 7mm Mashburn is a big supply of Bitterroots.

Bob did the 175 BBC penetrate with the 175 LRX? I would not have expected that.I have seen the 160 7mm BBC at work on game but not the 175.

That is a very qualified reason!

Nothing out-penetrated the 175 BBC.
My notes say it penetrated 12" in dry print.

(Have not tested the 30/175 LRX yet, but did test the 28/145)


On a side note, I shot a good sized Mule Deer buck this past fall with a Sierra 7mm 175 Game King.
At 580 yards it hit at an angled chest shot, penetrated and exited even going through some full stomach.
Buck went about 50 yards after being hit and dropped.

This field result confirmed to me that those dry paper test are a fairly good means to judge a bullet as the Sierra was only a 1/2" behind the Partition (9") in the test.

I had Leupold make me up a CDS dial for that Sierra load. I know it will work.

By chance.....I have a bunch of those Sierra's as well. Good info!

I'm in the same boat. Have a great load that runs the 175 PTs at 3050 from my 24" rifle with 73-74 grains of H1000 depending on the lot. It's very accurate and seems consistent.

Same for 160's and H1000. Guilty accurate as well.

I happened to grab a couple of pounds of RL33 to try. Getting 3100 from RL33 with the 175's but I'm not sold it'll be worth the effort honestly. It's just a rechambered M70 so there's only so much life in this barrel.

On the recoil deal. I'll shoot 175s all day long. 200's from my 300 WBY are a whole nother animal.

Ok Beretzs, ran your 200 gr bullet 300 Roy using the above 7.5 lb rifle, and 84 gr powder from the Nosler load book with 3050 fps. and the recoil is 42 ft. lbs.

That's about like my .416. I don't imaginge that there are many 7.5 lbs. 300 Roys out there but we have to use something for comparison.

YMMV

my mashburn likes the 150 grain class of bullets as well as all of the tsx slugs.

My two favorite powders are 7828 and norma mrp

federal case
150 swift s2 69.5 grains mrp federal magnum match primer. runs about 3185 from a bored out Remington 700. Has run .5 moa out to 400 which is the furthest that I've run it.

federal case
150 grain ballistic tip 71 grains 7828. federal standard primer. 3220 .75 MOA to 400

Why would you bother to build a gun around a bullet that overpenetrates?

W

79: Know a few people with Mashburns who like the 150's, the TTSX in particular.Dober uses then as well as 150 BT.

I had more trouble getting velocity from the 160s and 175s. It might just be my barrel though. I have a 1 in 9 twisted bartlein sitting here for when it goes. I hope that the 5r rifling doesn't cause any problems. I'd like to talk to that cover guy sometime.

My rifle also likes the 120 and 140 grain tax bullets

79: 160's and up is where 7mm magnums start to get stubborn,due to the fact they are heavy and more bearing surface. But mostly I've had little to no difficulty with 160-175's. My barrel is a Krieger. No problem with velocities of 3200-3250 with 160's,and 3050-3075 with 175's and H1000, RL25, etc.

If yours is a Rem 700 barrel I have noticed they tend to run on the slow side,although that's not universally true.Just a trend we noticed comparing my friends Rem 700's in different calibers to my Kriegers and M70's.

I think your Bartlein will be very good with no issues. Gene Simillion just got one in for my friend's Mashburn and is building another for a second friend, both on Bartlein barrels.

What are the options for 7 Mashburn dies? Is RCBS the only game in town and what do they get for a set? I missed a set on ebay that went for $33 because I wasn't there to bid :-(.

Does anyone rent this reamer and if not, is there a smith with one that would long chamber a barrel that I would finish? I'd prefer to do everything myself but the parts for this caliber are not generally available. Buying a new one is an option as well.

I think Redding also makes dies and additionally Bob and others have used 7 Rem dies to load. Contact Bob for exact details.

I bought/own my own reamer (JGS) and a set of dies from RCBS.

I've got an extra FL sizer I could sell you if interested. Don't have a seater to go with it though. PTG makes reamers.

Any particular reason(s) that you bought the JGS reamer over the PT&G?

Not especially. I bought it about 12 yrs. ago and they were the only ones that I found at that time that had a drawing to review before buying.

gzig: Dies are made by RCBS and have been for quite some time,although they tend today to be a special order whereas a few years ago they were on the shelf. Nevertheless they can be had in a few weeks.

RCBS makes not only the FL die set, but also the Form/Trim dies for forming brass.

My friend and I sent fired cases to Redding to have dies made,and Redding had never made them so I guess ours were the first sets they made.

For forming cases from 300 Win Mag, Redding did not feel a F/T die was required,the FL die being sufficient for initial case forming. Guess I can't argue with that, but I still use my F/T dies. I've done it both ways.

The cost for dies from either source is about $150 bucks last time I checked.

As to reamers I know there are smiths out there who could do a barrel. Gene Simillion built mine,and has a reamer and I think he'd be happy to chamber a barrel. I know Dave7mm on here had his smith do a rifle. Dave's smith has the reamer but I don't know who he is.

What was your trouble? Pressure signs before you hit the speeds you wanted or something different?

3200 with H1000 and 160 AB&160 PTs seemed very easy in my rechambered Winchester barrel, but understand all barrels are different.