Home Forums Hunting & Shooting Ask The Gunwriters Muledeer-7x57 velocities

I know you are a big fan of the 7x57 and I have all of your articles on the 7x57. We currently have 3 of the little jewels. One of the rifles is a 77 MK1 that has a very long throat. The rifle is exceptional as far as accuracy goes. It will shoot any factory load under an inch and some hand loads it throws into .375" ragged holes. The factory ammo chronys between 200 and 300fps slower than it does from our other rifles. Hand loads loaded all the way to max are about the same. Slow. The chamber isn't overly large. My guess is it has something to do with the long throat not allowing a normal pressure curve. The throat is so long that it isn't possible to start a bullet anywhere close to the lands because of the magazine length restiction. Powders I have tried in it are H4350,IMR4350,RL22,RL19,760,H414,H380 and probably a few more that I can't remember right off. The faster powders do seem to get closer to their repective velocities but still not what I am looking for.This furthers my belief that the low velocity is a product of the long throat. Because the rifle is so accurate I am very hesitent to mess with the barrel at all. Any ideals? Thanks, reflex264

I have an old well used M77 that is similar to yours. I had some old handloads made up for an M70 Fwt. that went 2875 fps with 140's. In the Ruger they were under 2700 fps. I just had to keep adding powder, it will go right at 3000 fps with 140's at 64000 psi. It also is long throated, but it doesn't affect accuracy. You can probably bump it way up with a little careful handloading.

I'm pretty sure Mule Deer wrote you could add IMR 4350 and stop at 2,800fps with a 140gr. bullet. 3,000fps sounds a wee bit fast for the 7X57.


Travis

Ah yeah 3K with a 140 is a bit agressive for a 275 Rigby, good speed for a 120 I'd guess though....

Dober

.275 Rigby. Damn Dober, you are old school....


Travis

Yeah, add more 4350 (of either kind) until the muzzle velocity gets up around 2800 with a 140.

Right now I am wondering how jstevens knows he is getting 3000 fps with 64000 psi with his 7x57 loads. Have they been pressure-tested or is the 64000 from QuickLoad or some other computer program?

I don't have a tested 7x57 load with a 140 grain bullet, but I do get 2864 fps at 56.6 KPSI with a 150 and H4350. My 7x57 is fairly long throated, and I load to .030" off the lands.

Depending on the bullet, 140's at 3K out of a 7x57 can't be impossible at reasonable pressures.

I've consistently hit 2875 fps (with great shot to shot consistency) out of a 20" M7 7mm08 using the 139 gr SP and 50 gr H4350 from MD's "Handloads that Work". Maybe my chrony reads that load funny, but it sure doesn't seem too "optimistic" with my other loads.

Given a bit larger case and a longer barrel, I can see 3K with the short bearing 139's as a top end load.

Then again, I strive for launching interlocks in the 2800 to 2900 range as things like WTD are often shot at ranges just beyond the powder burn.

FWIW,

GE

I have always been curious why so much attention is paid to velocity. I admit I don't experiment very much with reloading, just use the loads from the book and am satisfied. I start well below max and find a very accurate load with the bullet I intend to use and that's that. My 7x57 is loaded with a 175grNosler Partition (it was specified for that bullet when I had it built) and was intended for African plains game. The powder is IMR4350 which is also the major powder I use for literally everything. I know it's a couple of grains below max as that's where I usually end up (I,m not at home so don't have access to my records) with all my loads. I shot Kudu at ranges from 50 to 250 yds and they all dropped when hit properly. I don't own and have never shot a load over a chronograph so have absolutely no idea other than the book what the velocity was. I don't think the animals care and the holes in the paper I shoot are significently small enough to be proud of. Good nuff for me.

Well said. The 7 x 57 with 175 Partitions about a grain under max is a fine load. My wife is still using that load in a custom Mauser I put together for her the winter of '69, and she has access to more rifles than most women have ever even handled.

Wayne

The ideal with this rifle is to shoot a little flatter for the bean fields. Have 4350's on hand and will give it a whirl. WIth 175gr bullets the velocities are much closer to where they are supposed to be. I have been playing with 160gr partitions as well and would like to see them at least 2600fps. reflex264

Bean fields? That's what you're .264 is for.


Travis

Eleanor O'Connor was rather proficient with her 7x57 in the days when velocity was just sales pitch. It still is ???

JW

I will be using the .264 and a few more .264s testing them for a rifle builder. My son wants to carry the Ruger 7x57. Its not that it doesn't kill deer. He has probably shot 25 to 30 deer with this rifle. The shots in these fields get a little long. Most deer are shot past 300 yards. In order to get my trajectory scales like I want them I need about 250fps more than I have now. If it was just the general hunting this wouldn't be a issue. I would take this rifle with 175grs at 2450fps and go any where with it. reflex264

It's not the length of the throat, but the diameter of the throat that's causing your problem. The fact that the faster powders reduce the issue is another clue, as they will cause the bullet to opturate sooner, IE in the throat, and retaining more of the powder gas behind the bullet (where it belongs).

I'm just a newbie here, so if what I say is way off base, go ahead and laugh.

But I was thinking that you may want to try crimping your handloads with something like the Lee Factory Crimp Die. In theory, at least, with a firm crimp you should have pressure building to a higher level before the bullet exits the case, and the size of the throat becomes less of a factor.

Second, what do you think of using a 120-gr Nosler B-Tip at somewhere near 3000 fps? I took a look at it in a ballistics program and comparing the 140 gr at 2800 fps to the 120 gr at 3040 fps (Conley Precision Cartridges loads them to this velocity), the point blank range at +or- 3 inches is extended from 279 yards with the 140 to 297 yards with the 120.

This may not do you any good, but it is something to think about.

The 120BT is about the only bullet that this gun doesn't like. I have pushed the envelope with it a bit and it shoots 3-4 inch groups. It will throw 154SP, 139BTSP Hornady or 160gr Sierras into .75 or less. My thinking now is a 139BTSP or a 140 Ballistic tip. The crimping makes no difference in this rifle as far as velcity. Doesn't change a thing. When lab testing loads for the 45-70 and .450 Marlin the LFC didn't produce any kind of substantial gain in velociy although it did raise pressures. reflex264

If you want 250 fps more, get a .280

What I am talking about is just getting this one up to normal 7X57 speed. I do like the .280 and have hunted with one quite abit.reflex264

Reflex
I've GAINED 250fps (in a 30-06) by having the barrel shortened 1" at the chamber end, and recutting the chamber properly.
A chamber cast before "surgury" showed the throat was .3125 in diameter, the "post surgury" cast is .3085 in diameter. If the throat diameter is at bullet size the bullet acts as a plug to the gases, if the diameter is above bullet size the gases can blow past the bullet until it is in the lands.

Stop spinning your wheels, and get a chamber cast done and measured.