I have a budy who has an old, military issue 7mm Mauser made by Fabrique National. He wants to know what the rate of twist is so that he can fine the optimal bullet length. Also, what would be a good bullet and starting load for the rifle?

"To measure the twist of a barrel, use a cleaning rod and a tight patch. Start the patch down the barrel and mark the rod at the muzzle. Push in the rod slowly until it has made one revolution, and then make a second mark on the rod at the muzzle. The distance between marks is the twist of your barrel."

see: http://en.wikipedia.org/wiki/Twist_rate for more info.

-Bob F.

Military Mausers in 7x57 usually have a 1 in 9 twist, or close to it. Longer bullets often work better with a fast twist military barrel.

I had a military FN 98 in 7x57. On top of being throated for 175-gr. RN bullets, it had a fair amount of freebore/throat erosion. With 160-gr. RN bullets seated to the cannelure it shot about 4 MOA. I seated them so they were barely in the case and groups shrank to about 1.5 MOA.

Lightweight spitzers are legendary for not shooting well in military barrels, so I'd start with the long heavies.


Okie John

quote:

Originally posted by quarterbore:
I have a budy who has an old, military issue 7mm Mauser made by Fabrique National. He wants to know what the rate of twist is so that he can fine the optimal bullet length. Also, what would be a good bullet and starting load for the rifle?

The military Mausers were originally made with a twist for a 175-grain roundnose bullet, and even after they changed to sj=horter, lighter spitzer bullets, it seems that the twist was not changed. It was originally 1/8.5", or thereabouts. I have a Venezuelan M24 made by FN. It shoots 175-grain bullets very well. But it is also very accurate with 140-grain and 150 grain spitzers.

This is with a 150-grain Nosler BT and 50 grains of IMR 4350, MV 2700 FPS....

The military twist is 1x8.66 which is so close to 1x9 it isn't even worth quibbling about. My 7x57mm has this twist and it does an excellent job with 160-grain class bullets. In fact, I haven't even shot any 154, 150, 145, 140 gran or even 139 grain bullets through it, just 160 grain and 162 grain Hornady SSTs. Have a good day. Tom Purdom

My first "sporter" was a converted Chilean Navy M1895 Mauser, 7mm, of course, and it had the 1-9 twist. Was very accurate with ancient Remington 175 grain FMJ ball ammo, such that in my first "competitive" try on the Navy short course circa 1965 I shot a score 245 out of 250 points. Don't remember the X count, but it was a biggie. Those good old boys at Mauser knew what they were doing.

LLS

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My "Plezier" Mauser, ( DWM M93 action) has under the barrel in the chamber area, 222,5. I understand this is the twist rate: 1 turn in 222.5 milimeters or 1 turn in 8,7598...inches.
Am I right ?
PH

Alf,
I have some questions four you as you seem to know a lot about old Sporting Mausers (I saw the pictures of your very nice rifles!):
1-Are you sure Rigby used the German made M93 barrels ?
2-Are the M93 barrel threads, (the diameter and the lenght) the same as in the intermediate action Rigby mostly used in their .275 ?
Thank you and my Best Regards.
PH

My FN Venezuelan LOVES RP Brass, F210GM, 50 H4350, 139 Hornady SP Interlock @ OAL of 3.180. Stoney Point your own, this is .005 off the lands for mine. Work up to the charge ... usual disclaimers apply.

I have a Remington 700 Mountain Rifle with a 22 inch barrel in 7x57 Mauser and the tech dude at Remington told me the twist was 1 turn in 9 inches.
The 140 grain Partition's I chronied clocked in at 2825 fps with 50 grains of H4350. I have not chronied the new load of 52 grains H4350 yet,I'm hoping for really close to 3000 fps.