Anyone ever try Reloder 7 for 7x57 Mauser?

[Newtosavage]

When loading different weight bullets for my .308, one of the recipes I saw for 125's used Reloder 7, a powder that my local Bass Pro always keeps in stock. I bought a pound, used it for about 10-15 loads in my .308, and decided to go with heavier bullets in that gun.

Now I'm wondering if I could possibly use it in my 7x57 for 120-grain bullets. I see Reloder 7 listed for similar calibers (257 Roberts) and bullet weights, but never for the 7x57.

I have a short (18.5") barrel on my Ruger, and was thinking a faster powder might compliment that short barrel well with the lighter bullet.

Any ideas?

Thanks.

 

[stoky]

IMO, it's kind of fast for 7x57. Reloader 15 or 19 would be better.
In my experience, the best powders for 7x57 equate to .30-06, more so than .308.

 

[Newtosavage]

I figured it was a little fast, but again, I have an 18.5" barrel so I thought those may cancel one another out.

I don't have to use it, but I have no other use for it so I thought I may give it a try with light bullets. Thanks for the tip on the '06. They show a 100 grain bullet load for R7 with that round.

 

[GooseGestapo]

Like others stated, it's faster than traditional powders for 7x57. However, it works quite well for reduced recoil and cast bullet loads. Look for cast bullet data (can be used with jacketed bullets too).
Lacking data, you can use IMR/H4198 data as a starting point. Rl7 is a tad bit slower than the 4198's so it takes about 5% more #7 and yields about 5% less pressures, but at same velocities.
I've mostly used Rl7 in .30/30 and .300blk with cast bullets. Works great, and I prefer it to 4198's. It does mild to wild in the .45/70, too!

 

[Newtosavage]

Thanks Goose. That's very useful information. I appreciate it.

Will crank out a few at the range with RL7 today, over a chrony and see what she reads. I want to see what signs of pressure may show up as well. If RL7 is good for light bullets in the '06 and 308, I'm not sure why it wouldn't work well for light bullets in the 7x57.

 

[25-20 WCF]

Lyman's #46 does show pressure tested data for the 7x57 and a 120-grain bullet with Reloder 7.

Starting load:
30.0 grains - 2353 fps - 32,200 CUP

Maximum load:
33.0 grains - 2630 fps - 41,600 CUP

It was proven by IHMSA shooters and others over 30 years ago that the powder which gives the highest velocity in a long rifle barrel usually also gives the highest in short barrels. In the Lyman data, Reloder 7 produces almost 450 fps less than slower, more appropriate propellants.


.

 

[Newtosavage]

Thank you! I'm now wondering if the 40 grains of RL-7 I loaded is going to be way too much...

I'm sure those Lyman loads were intended to be safe for older Mausers. Mine is a new Ruger 77.

I think I'll pull those bullets and drop back to 33 and start from there.

 

[Newtosavage]

Started out with 33 grains today, and worked up through .5 grain increments to 36 grains. 33 grains of RL-7 under a 120 grain sierra bullet felt like a pop gun. Hardly any recoil at all. But the accuracy with the RL-7 appeared immediately. Both 33 and 34 grains shot at or under an inch, which is half the group size I've been getting with 4895 and those bullets, or with the factory Prvi loads. Group size stayed steady and zero signs of pressure as inspected by me and a very experienced hand loader who happened to be at the range with me today. So I'm going to keep working up from 36 to 40 grains and see how it goes.

Unfortunately my Chrono was acting up when I was shooting the RL-7 loads, so I didn't get any speed data, but it came back to life later and I hope to get some speed data on the hotter loads so I can see where I'm at.

With any luck, the groups will stay good through a 2700-2800 fps. load with that 120-grain bullet, with no signs of pressure. That would make a great, flat shooting deer load.

If my wife or daughter ever use that gun. I now know that 33 grains of RL-7 not only shoots well, it barely kicks at all. Good to know.

Oddly enough, H4895 and 120 grain bullets don't mix well at ALL in that gun, but the 162-grain SST's shoot very well over it. Go figgur.

 

[Newtosavage]

FWIW - got some chrono #'s from RL-7 the other day.

RL-7, 7x57 Mauser, 120-grain Sierra Pro Hunter

36 grains - 2680 fps
37 grains - 2700 fps
38 grains - 2770 fps
39 grains - 2815 fps
40 grains - 2870 fps

At 40 grains, the bolt was getting a little tight, but I still saw no flattening or cratering of the primer. In my gun I'm not going past 39 grains though.

37 grains proved to be the most accurate, with the best groups I've shot so far out of my 7x57 Ruger 77 RSI. That gun only has a 18.5" barrel, so I'm giving up a good 100-150 fps. versus the published data with most loads.

Recoil in my 7.5 lb. rifle reminded me a lot of a .243 with 100 grain bullets.

 

[Poper]

37 grains proved to be the most accurate, with the best groups I've shot so far out of my 7x57 Ruger 77 RSI. That gun only has a 18.5" barrel, so I'm giving up a good 100-150 fps. versus the published data with most loads.

It is unlikely any deer within 250 yards will know the difference.
I suggest sticking with the most accurate powder charge if you intend to continue to use RL7. JMHO

 

[Newtosavage]

That's what I plan to do. I doubt I'll find much use for a 120 grain bullet traveling 2700 fps, but you never know. Would be a good load for my daughter since it kicks less than her .243 does.

I plan to use 140's or 160's to hunt with. I prefer to lob a slow heavy bullet. Less meat damage and I have 35 years of tracking experience, so if they wander a little ways before they drop, it doesn't worry me.