Newbie with a 7mm Mauser question

[oldcorps76]

My first post, so be gentle ;)


In 1980, at the tender age of 26, I was looking for a big game rifle and decided nothing out there interested me. So I embarked on a 4-year and lotsa $$ (a little at a time) quest for what I considered the perfect rifle. Ended up with a Argentine Mauser-actioned 7mm Mauser with a Douglas premium air-gauged featherweight barrel and very nice French walnut stock. Tips the scales at 7 lbs with Leupold 1-4x. Got 3 elk in the only 5 years of hunting I have done with factory 175 gr Federal SP. Shoots like a laser beam.....

Alas, it sits unused most of the year. I am a pretty experienced caster for handgun (.45 Colt BP; .44 Mag and Spl; .357/.38; .45-70 BP rifle, all with SPG lube thru a Saeco lubri-sizer). So I thought me, why not do something similar with the Mauser in the off season? Brings me to the list.....

Any suggestions on the following, in any order:

- Use of SPG as a smokeless powder rifle lube?
- Suggested moulds, seeing as how my rifle seems to like long bearing surfaces in the 160-175 gr range (not sure of the twist rate).
- Gas check or bare base?
- Suggested loads?

Appreciate it!

AK

[Larry Gibson]

oldcorps76

Any suggestions on the following, in any order:

- Use of SPG as a smokeless powder rifle lube?

SPG has been well tested and will work fine for regular 7mm loads upwards of 1900 - 2000 fps.

- Suggested moulds, seeing as how my rifle seems to like long bearing surfaces in the 160-175 gr range (not sure of the twist rate).

Current available moulds I would suggest the Lyman 287641 or the RCBS 7mm-168-SP. However, if you can find an older Lyman 287405 or the original RCBS 28-168-FN they would be my choice. Both at Lovern designs and shoot very well in the 7x57. I've the 28-168-FN and it shoots very well in my sportered M95. All of the moulds mentioned do quite well in modern barrels with 9 - 10" twists.

- Gas check or bare base?

GC'd for best performance and accuracy. I would suggest slugging the throat of your rifle and sizing for a tight slip fit.

- Suggested loads?

With any of the mentioned bullet my first work up loads would be with 4895. I'd start at 22 gr, use a 1/2 gr dacron filler and work up in 1/2 gr increments to 28 or 30 gr depending on the bullet weight. Best accuracy will probably come in around 1750 - 1850 fps. I would then try a slower powder like AA4350 and a faster powder like 24--, 4227, 4759 or 5744. Loads for them would be different of course but data is available. However, odds are id find a very good load with the 4895 and stick with it.

Larry Gibson

[Char-Gar]

I have used SPG in handgun loads, but not in rifle, so I can't speak to it's suitability for that application.

I do not cast for a 7mm, so again others will have to pass on their experiences and recommendations.

I have shot many, many thousands of cast bullet loads in rifles, and I would strongly suggest you start with a gas check mold design. You will find success and happiness quicker if you do.

Larry is a knowledgeable and experienced cast bullet shooter and his counsel is always well founded and can be relied upon.

To close, welcome to the fold. You have made an excellent decision that will give you great enjoyment.

[plainsman456]

Also don't overlook the 135-139 grain boolit mold that was done for the 7mm TCU.
In my 7x57 it shoots to the same point of aim as my jacketed bullets in 139 weights.I am just now playing with a mold that casts a 168-170 grain.

[Nrut]

Group Buy from this thread:
http://castboolits.gunloads.com/showthread.php?t=111851



http://i69.photobucket.com/albums/i80/swedenelson/1111-154286407150GrFN.jpg


Hint...:mrgreen:

[9.3X62AL]

Can't help with the questions--but that rifle sounds like a very well thought-out assemby.

[turbo1889]

My first post, so be gentle ;)


In 1980, at the tender age of 26, I was looking for a big game rifle and decided nothing out there interested me. So I embarked on a 4-year and lotsa $$ (a little at a time) quest for what I considered the perfect rifle. Ended up with a Argentine Mauser-actioned 7mm Mauser with a Douglas premium air-gauged featherweight barrel and very nice French walnut stock. Tips the scales at 7 lbs with Leupold 1-4x. Got 3 elk in the only 5 years of hunting I have done with factory 175 gr Federal SP. Shoots like a laser beam.....

Alas, it sits unused most of the year. I am a pretty experienced caster for handgun (.45 Colt BP; .44 Mag and Spl; .357/.38; .45-70 BP rifle, all with SPG lube thru a Saeco lubri-sizer). So I thought me, why not do something similar with the Mauser in the off season? Brings me to the list.....

Any suggestions on the following, in any order:

- Use of SPG as a smokeless powder rifle lube?
- Suggested moulds, seeing as how my rifle seems to like long bearing surfaces in the 160-175 gr range (not sure of the twist rate).
- Gas check or bare base?
- Suggested loads?

Appreciate it!

AK

1. ~ My use of SPG has been extremely limited so can't really give you a mark on that one.

For lubrication technique in general I can tell you that I use tapered Lovern boolit designs almost exclusively in the 7x57mm and that I lube the bottom few lube grooves that will go inside the case neck with a hard stick type lube and use 3:1 JPW/X-lox heated in a double boiler to dip lube the exposed nose and bearing length of the boolit that is outside the case as the final step after the boolits have been loaded into the cartridge (holding the cartridge case by the tail with the nose down and dipping the exposed boolit in the heated lube mix) . That mix dries as a thin hard wax coating that clings tenaciously to the boolit and doesn't pick up dirt and junk and serves to lubricate the bearing length of the boolit that is outside of the case neck. You may not need to do this but I have found it helpful with this and other rifle cartridges, especially smaller caliber rifle boolits with long bearing length boolits with lots of bearing length outside the case neck and in the throat of the rifle.

2. ~ As I said above tapered Lovern boolit designs have always shot best for me in the 7x57 especially the older military rifles.

3. ~ Gas checked would be best for someone just starting into loading cast boolits for high pressure bottle neck rifle cartridges. Eventually you will probably want to play with plain base boolits as well but you can easily have the gas check shank reamed out on one cavity of whatever GCed mold you end up buying later on so the mold drops one cavity as a plain base and the other cavities GCed.

4. ~ Personally I am a huge fan of full case compressed loads of military surplus 50-BMG type ball powders in the 7x57 cartridge (along with a lot of other rifle cartridge but the 7x57 with a heavy 170+ grain boolit really shines) for fun loads that are cheap and provide some excellent performance velocity that aren’t too far south of the 2,000-fps threshold.

[oldcorps76]

Wow - thanks all, so far...

Gonna have to take some time to digest all that advice, but is sounds like good stuff to me. Oh, and 9.3, thanks for the compliment, I thought about that configuration and caliber for about a year and a half before I put $$ on it, and it even evolved from there - took 4 years to complete. For me, a more perfect mountain rifle could not ever be.

[oldcorps76]

By the way...I am using wheelweights for all my casting, and I'll be glad to take comments on that. I may post another general thread asking about good sources of different alloys of lead.

Just put the recommended RCBS mould, 531 top punch, and Saeco Lubrisizer .285 die on my Midway wish list ;)

[turbo1889]

. . . Just put . . . Saeco Lubrisizer .285 die on my Midway wish list . . .

Are you sure that 0.285" is the right size for your rifle? The internal dimensions and thus the correct cast boolit size for each particular gun vary slightly and that sounds a little small for a 7x57 even one with a custom barrel with "tight" barrel and chamber dimensions.

Hang around this board long enough and you will come to the conclusion that the operating wisdom for "correct" boolit diameter for each particular rifle can usually be defined as one or a combination of the following:

~ 0.001" to 0.002" larger then the major groove diameter of that guns barrel
~ 0.001" smaller then the inside diameter of the neck of a fired casing of a full power load fired in that gun
~ Exactly equal (to the thousandth of an inch) to the throat diameter of that gun

Again 0.285" sounds a little small to me but if it really is the right size for your gun then go with it. Just realize that an under-size boolit is the number one reason for problems both in terms of accuracy and leading of the bore with cast boolits.

[Bret4207]

Welcome Oldcorps, (USMC?). Anyone that chooses the 7x57 is 3 steps ahead of 90% of the rest of the shooters out there to start with. I'd be inclined to follow Larrys advice. You have the benefit of a non-military barrel and chamber, which means you should have far fewer problems with oversize issues. WW is an excellent starting point for an alloy. I've taken plain WW well past 2K fps in 30 and 35 cal rifles. Don't immediately rush into the "BHN game" because harder isn't better, it's just harder. A GC mould like the RCBS 7mm-160FN is an outstanding choice. It's worked well in my ratty of 95 Mauser with it's pitted barrel in the 16-1700 fps area.

Start low and slow, observe, record, enjoy. Make sure that barrel is very, very well cleaned of any jacket fouling before delving into cast with it.

[oldcorps76]

Bret/Turbo - thanks, esp for the compliment about my caliber choice. Bret, no, I was career Air Force. The 'oldcorps76' refers to VMI and the year I graduated. Some of us curmudgeons who went there before SCOTUS mandated co-education call ourselves 'the Old Corps' ;)

30 years ago I narrowed the caliber choices to 3: .308 Winchester, 7mm Mauser, and .257 Roberts. Quickly dropped the .308 (like the sectional density of smaller diameters) and very nearly went .257, but figured the 7mm would be a hair superior with heavier bullets and have not been disappointed.

I guess I need to measure the bore because I thought 7mm = .284, and from what I saw the .285 is the size Saeco offers on their dies, at least from Midway. I use .460 sizer for the Lee .405 hollow base bullets I cast for the .45-55 BP cartridges I load for my Harrington trapdoor carbine and Richardson and it also shoots like a laser, with no leading.

[oldcorps76]

Also thanks for the wheelweight endorsement. They sure are easier to get than most other casting materials.

[turbo1889]

They also offer a 0.286" die and like most companies you should be able to order a custom one larger if it was necessary. I've just seen a lot of new guys about pull their hair out with cast boolit loads that just won't shoot for them only to figure out that all they needed to do to fix the problem was a slightly larger boolit after trying all sorts of other stuff first.

Now it is true that most of my 7x57 guns still have their military barrels (but not all) but I have used boolit diameters up to 0.288" in some of them to get them to perform with cast lead boolits. Long story short I suggest you first measure the inside neck diameter of a fired case from that gun and then slug your barrel. Those two measurements (or even just the first if you have a tight cut chamber) should get you the info you need to make an educated choice on the sizing die. Since your gun has a new barrel instead of the original military barrel doing a chamber cast or doing a hammer swagged throat impression shouldn't be necessary since I doubt your custom barrel has a big loose throat like one can sometimes encounter in military barrels.

[oldcorps76]

"Long story short I suggest you first measure the inside neck diameter of a fired case..."

Great suggestion, one of which I would never have thought myself. I have calipers and sure as hell like taking the easy road if it works. I'll let you know....and thanks again!

[robroy]

oldcorps76: [I]'m lovining this thread since I have an FN 98 still in millitary dress with a douglas barrel, wallnut stock, and double set trigger waiting to do much the same thing. The info this thread has generated is of great interest.

I got a GB 7mm 150 bore riding hunter which is outside the envelope of large bearing surface boolits about which you asked. I may shelve that Idea and try one of the molds suggested here.

Thanks again for asking these questions./I]

[oldcorps76]

Hey...that's the beauty of the 'net. All that experienced shared at the fingertips. Glad I could be of help to someone else, even if indirectly. Your rifle sounds nice. One of my regrets is the smith that made my rifle had a lovely prewar Oberndorf Mauser action with butterknife handle and DST, back in 1981 for $325. A few $$ out of reach so I bought the Argentine. It all worked out but that Ob was beautiful and what a Mannlicher it would have made....sigh.....

Measured and looks like .286. Midway wish list changed to the larger die.

Thanks again!