I believe I have one that has a rather short throat...but I need to know if it is too short; the Hornady manual lists a max c.o.l. of 3.00" using a 139 gr. HDY flatbase SP. Using a stoney point gauge, my "to" lands distance with the 139 gr. HDY FBSP is 2.590". If I load to book C.O.L. of 3.00", I get land marks on the bullet.

What say you?

Are you sure the marks are from the lands and not the seating die?????

Provided you're getting land marks on the bullets, just seat with a C.O.L. short enough you don't get land marks.

In loading for rifle cartridges the size of a 7X57, a cartridge a little longer or a little shorter than the manual value doesn't matter much. The cartridges need to be short enough to feed through the magazine and short enough so that when the cartridge is chambered, the bullete doesn't engage the lands.

Based on the two I own I'd say your throating is a good bit short. I get OAL= 3.00" to 3.2" with bullets from 140 gr psp to 175gr. RNs. The throat depth on my two varies about .050"one to the other.

The slope of the leade is so long that seating the bullets .010 deeper may eliminate the marks.

I am intrested to know what type of rifle is giving you this situation. ? is it a factory barrel ? If its a military rifle its entierly posible somebody turned the barrel back a couple threads. If your magazine is longer than the loads you can have a smith ream the throat a little.
I have loaded for the 7X57 for years and you can really boost the preformance in a modern fifle if you can seat the bullet out a little and increase you powder capacity. DO NOT DO THIS on an early spanish mauser. But On a 98 mauser or a ruger CZ Remington, or other modern rifle, the troating can really make a difference...tj3006

Dyslexia kicking in: the "to lands" measurement is 2.950", not 2.590". This rifle is a custom, built on a small ring Mexican Mauser with 21" Douglas barrel. The mag is such that I could get some additional seating length but the throat confines prevent such.

Sounds like a heck of a nice rifle, especially for NW Oregon where, I'm told, ranges are pretty short. If it shoots for you, I'd leave it alone and load it short with a little less powder.

If you want more power, rethroating would be a perfect excuse to rechamber to 7x57 AI at the same time.

There comes a time in any project when you call it good and go shoot the thing. Only you know whether you are there with this rifle or not.

Good shooting!

Alan,

good advice already here.

I agree with what's been said but bartche's (thanks for changing the photo - a BIG improvement) initial call on the extremely short throat was the key but then you changed the parameters.

I get OAL in a 7x57R as short as 2.92" with a particular bullets and then into the +3.10" with others and the rifle is a modern chambering.

Sounds like your nifty shorte(er) barreled Mauser is a nice piece. Do stay away from engaging the rifling with bullets though - drives pressures up and could leave you with a bullet left in the throat and an action full of powder when you least desire such an occurance.

While on the subject of 7x57 & the Hornady manual, I have an old Hornady book from 1980? that shows 7x57(22"bl) getting 154gn-2900fps and 160gn-2800fps (3.0"oal)
Any one else achieving such figures with similar load length&barrel length???
Do more recent Hornady books state similar 7x57 velocities?

Alan.
I live in portland, and if you want to know a real good smith who would do a great job throating you chamber to fit your mag, go to H&K gunsmithing in Forest grove. Its right on pacific ave. kurt loves mausers and a small ring Mex is one of the cooler mausers.
You should be able to get 2850 or more easy
with your 21 inch tube with a 140 grain bullet.
That would make your rifle a great choice for any deer hunting in oregon.
Really cool rifle...tj3006

[QUOTE]Originally posted by Woodjack:
While on the subject of 7x57 & the Hornady manual, I have an old Hornady book from 1980? that shows 7x57 getting 154gn-2900fps and 160gn-2800fps (3.0"oal)
Any one else achieving such figures with similar load length&barrel length??? NO! the closest was 2581 with a 160gr. bullet in a 19" barrel. This had hard bolt handle lift. Another 5" of barrel might have kicked the velocity up to 2700fps. but certainly not 2800 fps. Not in my rifle. roger