Home Forums Reloading Big Game Rifles long throat and a short bullet

I've got a 7x57 Mauser with the long throat, but the rifle twist measures to about 1/10. It's always been pretty picky about what it will shoot well, mainly it likes Hornady 175gr RN bullets which are discontinued. I've got a small stockpile, but I'd rather not use them for plinking, so I figured I could use up a bunch of old Speer 130gr BTSP's for that purpose. But when I ran one through the chamber with a Hornady OAL gauge it turns out the boat tail will be disengaged from the case mouth before the bullet reaches the rifling. This isn't something I'd ever thought of occurring, hopefully it's not going to make a difference but I figured it couldn't hurt to ask.

What's the diameter of the throat?

Shouldn't hurt a thing, but it may be real touchy with finding a sweet spot for powder charges.

Not a Mauser, but I have a 303 Savage with a long and massively overbore thoat (.315 throat .308 bore) It shoots short bullets fine, but velocities run very low, and resizing the brass takes some elbow grease since the necks and case mouths balloon out so much. It's kind of finicky to load for; just a few tenths of a grain is often the difference between buckshot and good group.

130gr Speer FN and 110 Sierras will touch shots at 50yds with irons from it, and there is a 1/4 inch bullet jump between the end of the case mouth and the start of the riflings.

No clue there mathman, I can say it's an older tang safety M77.

Pretty sure other long bullets are available

One of the best loads I ever worked up was a short bullet in a long throat. Remington 700 factory barrel. Jump to lands was .250".

zcm82, I can say it's at least big enough that fired brass will let .284 bullets fall all the way into the case. So I'm likely in a similar situation.


anothergun, true. These were just the first I picked up off the bench because I never used them for anything.

Feral_American, good to know. I'll be looking at about a 3/8" jump to the lands with the 130's. The 175's are closer, but it only seems to like the RN variety. Pointed 175's are all over the place and look to start trying to keyhole.

Both the older 77s and No. 1s in 7x57 had very long (and often "loose") throats. Consequently they often did require longer bullets seated closer to the lands to group reasonably well.

That doesn't mean they couldn't shoot "hunting accurate" with lighter, shorter bullets. I had a 7x57 No. 1 that would only put three 140-grain Ballistic Tips into around 1-1/2" at 100 yards, which today sounds pretty pitiful to many hunters. But it killed deer-sized game out to 350+ yards every time I shot at one....

I'm not worried about shooting tiny little groups. I'm more looking for something that I could cobble together from old, unused components stuffed in the back of the bench. I came across the 130's and some old imr4895 and 4064 and thought that could make some pleasantly soft plinking ammo that's easy on the brass.


Unfortunately the necks are starting to split on me, so I likely need to order a new batch of brass for the actual hunting ammo.

I have a 1956 Mannicher carbine 7x57. When I got it the only 7x57 factory ammo I could find was Remington 140gr Corelokts. It grouped rather well with that ammo. I load 140gr Remington Corelots seated to the same OAL as the factory ammo. It has a long throat too and I tried seating the bullets out and the grouping went south. I suggest flat base bullets in the weight you choose.
Dave

Anneal them.

And there's the problem. I got a tang safty Ruger in 7x57 when they first came out. Beautiful rifle but lousy shooter. Just before giving up on it I tried 154 gr Hornady RN bullet's amd suddenly it became a shooter, no idea why. Don't recall seating depth with it any more but in those days I never loaded shallower than one bullet dia. Now with those light bullet's and long throat you simply don't have a choice where to seat the bullet's. Two thing's, seat the bullet's one cal deep and what ever you get call it good or, have the rifle rebarrled and chambered with a dummy round the way you want it. That Ruger broke my heart. Looked so nice and shot so bad!

I agree to anneal the necks on the brass that's splitting.

On the short bullet and long throat about all I can suggest is try various seating depths. You just might get lucky. back in the early 1980s I had a Ruger M77 tanger in 7x57 that had a long throat. Back then I was trying to get a deer load using 140 gr. bullets with not much luck. I finally found a useable load with the Sierra 140 gr. Pro-hunters bullet was seated out about as far as I could get away with and still keep the bullet from falling out while being fed into the chamber.

I also have a Ruger #1A 7x57 that had a throat so far out of specs that I had to send it back for repair. (2.5"+) It shoots decently now. (1.0" to 1.5" depending on the bullets.)

PJ

My first rifle was a sporterized SMLE No 4 mark one. The SMLE's were only good for 4 inches at 100 yards. I had a gunsmith look at it and he said they took too much wood out of the stock, so he bedded it. At the time I didn't have the money so he didn't finish the job. The glass wasn't even cured when I picked it up. That's another story. I bought a synthetic stock and it basically shot the same. However..... I bought PMP ammo from Africa, which isn't made anymore. Shot one inch groups at 100. I was excited. Might have been 180 grain bullets. Ever since I stumbled across neck tension, there's no turning back. Back then I would have never knew. A guy who owned a gun shop reloaded for people, and his son said let my dad reload for you and I can guarantee great accuracy. Most likely he knew about neck tension.

In short... Bedding definitely helps along with a free floating barrel, some free floating helps some don't, Some like bedded barrels. If you consider bedding bed the barrel too, later you can float it and see. It's worth the work.

One other thing.. try a Lee Collet die and order a oversized mandrel. It's only 10 bucks and a Redding body die. The body die stays away form the neck.

Some rifles need help some don't.

Maybe check the front recoil lug screw and make sure it's not binding the action with too much pressure to up set accuracy. Action screws should be evenly torqued kinda like a head on a engine block.

Why do you want an oversized mandrel?

I know the feeling, the original owner must have felt worse though. They took an old M77R and chopped the barrel to 20", added front and rear sights and restocked it with a nice full length mannlicher style stock. My wife bought it for me after seeing me drool over it on GunBroker for a couple of weeks. She calls it my table leg because she thinks it's butt ugly LOL.