PDA

View Full Version : 7x57 advice wanted



offshore44
03-24-2012, 02:10 PM
Well, it seems the wife is finally getting into the spirit of casting...

She has been watching my progress with casting for several of my rifles, and with the cost of reloading components getting pretty steep, and harder to reliably come by, she asked this morning about getting her set up with a cast boolit for one of her rifles. She currently only shoots cast out of her 1911, and sees the benefit.

Out of all of her rifles, her 7x57 Brno Model 98 Mauser seems to be the most likely candidate. This rifle is old, probably from around the late 1940's to very early 1950s. It is in VG to almost perfect condition. With Sierra 130 grn Match Kings and the right load it is a one hole, cold bore shot rifle. That's three shots out of five into one hole at 100 yards. She has done that on more than one occasion recently. The potential is there.

What molds should I look at to duplicate that precision with cast? What powders and loads? Considering the age and origin of the rifle, I am expecting to get a non-standard bore and groove diameter when I slug the barrel. I would need to take that into consideration when I purchase the mold and the sizing dies. Comments on that would be appreciated. I would also like to keep the boolit weight in the 130 to 150 grn range; she doesn't like to shoot the heavy 175 grn hunting bullets that I got for her to try. I guess that I could back the velocity off to mitigate the recoil some, but I would like to push something in the 2,200 to 2,400 fps range that the rifle seems to like in j-words with a cast boolit. 2,400 fps seems to be a stretch for cast in the 7x57. That means harder alloy and gas checks I suppose.

Anyway, I would appreciate others experiences and suggestions as guidance on getting her going with her classic hunting rifle.

I suspect that this rifle may also be a candidate for a paper patched boolit as well, but that seems to be pretty small. My 8x57 is about the smallest that my current level of manual dexterity allows. Ideas in that area would be appreciated as well.

Thanks a bunch for the input!

runfiverun
03-24-2012, 05:25 PM
it means harder slightly exotic alloys, sorting, and load development.
the rcbs 145 silhouette is excellent in most x57's with a tighter throat, the 168 does better with a longer throat.
powder choices for 2400 fps will be the same load you use now.
personally i'd get a lighter load worked up and then try to make inroads from there.
or call veral smith,buy his book,and send him some impact slugs for a custom mold.

offshore44
03-24-2012, 06:09 PM
it means harder slightly exotic alloys, sorting, and load development.
the rcbs 145 silhouette is excellent in most x57's with a tighter throat, the 168 does better with a longer throat.
powder choices for 2400 fps will be the same load you use now.
personally i'd get a lighter load worked up and then try to make inroads from there.
or call veral smith,buy his book,and send him some impact slugs for a custom mold.

Thanks runfiverun...

I have no idea where this particular rifle falls in the throat category. 'haven't even slugged the bore yet.

I usually start out with light loads and end up at about 1800 to 2000 fps or so. Just 'cause the rifle likes j-words at 2400 doesn't mean that the rifle will like cast at that velocity. I was more wondering if it was reasonable to think that it was possible more than anything.

What do you mean by exotic alloys? The most exotic thing that I have on hand is a few pounds of "mixed" lead that has wheel weights, Oregon Trail cast, pure lead, Lyman #2, bugs, dirt, range scrap and probably a few other things in it. It comes out to about 18.6 +/- BHN.

I'll give the RCBS mold a looking at. Thanks!

runfiverun
03-24-2012, 07:44 PM
i hate to open this can of worms again.
but the x57 usually has a pretty quick twist rate 9.5-1 or so.
adding stuff like copper [and zinc] to an alloy will allow you to push things a bit quicker/harder.
i have a few of the x57's it is my favorite jaxketed round out there.[i have the 25,6,6.5,7 plus an ackley and an icl also,and 8]
and hopefully a 30 on the case in a while. [i got the parts]
it's not hard to get good accuracy from the 7 but the velocity takes some extra work in the whole process.
it's my experience with them.
others have just stuck the boolit in the case and were happy [dunno] or they were lucky...
start low and work up,change to slower powders as you go up, and fillers can help some loads..

offshore44
03-24-2012, 08:01 PM
Thanks runfiverun. That's good to know stuff right there. I know that the 8x57's have a pretty quick twist as well, and I just shot heavier boolits at a lower velocity and got essentially the same results as lighter / faster. Different trajectory of course. I'll see about doing some recoil calculations with different weights and velocities and see what I come up with. (The wife ALMOST will shoot one of my heavy - slow 8x57 loads...almost) She just really likes her "Super Seven".

6.5 mike
03-24-2012, 08:07 PM
If the rifle is post- war it may be what we figure are normal specs, 0.284 ish groove. If it pre- war it may have the older 0.318 ish bbl. Best bet is slug it & go from there. If you have any of the cases that were fired in it that may help also.

The 7x57 is a great cailber to work with. Ben has a very good post using the lee 7 m/m soupcan. I have a couple that Wayne S gave me & they look real good, bout 140 grs. Paper patching is another way to keep the fps up, I'm using it in a 7 m/m tcu, & 2 7x57s. Have fun with it :popcorn:.

skeet1
03-24-2012, 09:15 PM
I have an old Ideal 285308 that I have shot in several 7X57's and have found it to be a good bullet. If I remember right I think it weighs about 160gr. I have a .287 sizer and size to that diameter.

Ken

offshore44
03-24-2012, 10:19 PM
Thanks guys.

As near as I can tell, it's post war, but just barely. It's got the sporter action without the thumb cut. No provision for stripper clips / chargers. The safety on this thing is really nice. It a small thumb lever on the left side of the action. Two position. Retracts and locks the firing pin but not the bolt. The bolt shroud is enlarged on the left side to accommodate the safety.

It sure shoots like a house afire! Handy weight for the wife to carry as well.