Low velocity in 7x57

MD

MD

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I went with a buddy to the range last month and using his chrono found that my 7x57 was shooting 140 grain Nosler Partitions at 2550 fps. I was expecting about 2700 fps

The cartridges were loaded with 48.5 grains of H4350.

We double checked the weight of the powder by opening one up.

So I ended up shooting about 2-inches high at 100 yards.

They didn't have a 200 yard range there.

Do you think the 150 fps difference would make a significant drop in the bullet at 200 yards?

My buddy said that the low fps could have been caused by it being new unfired brass fire-forming and the short (21-inch) barrel in my Husqvarna Lightweight.
 
You might have more leade or freebore which can drop pressures too. I didn't have much success with H4350 velocity wise in my rifle but it is not a HVA.
How did the load group?

Inside 300yds 150fps wouldn't amount to much difference. Depending on how the load shot should be the deciding factor. If it shot well I think you are good to go.
 
I have had good success with W760 and IMR 4064 in 7x57 with 140's. With the 21" barrel and likely a long throat you will have slightly lower velocities--that was the case with my Husky when I owned one..
 
Brazilian

I suspect your Brazilian has a 29 inch bbl, while the HVA has a 22 inch bbl.

Freebore will make a significant difference in velocity. I wouldn't worry about it much though, unless it's effecting your accuracy. There isn't a deer in the world that can tell if a bullet is travelling 150fps slower.

As for increasing velocity, try different powder. As mentioned below, H414 or W760 gives excellent velocity and accuracy with 140 grain bullets.

The Brazilians used a 140 grain bullet and loaded it up to 2900fps at 40,000 psi in their 1908 and 1935 mausers with 29 inch bbls. In a 24 inch bbl the velocity dropped off to 2750fps.

A load that I use and recommend, is from the Lyman manual. 49.0 grains of W760, 140 grain bullet, standard primer, 2721fps from a 24 inch bbl at 39,700 psi in a universal receiver.

I own and shoot several 7x57 rifles. This load will shoot very well in all of them and is safe in the older 93 and 95 mausers as well.
 
Thanks gentlemen.

We were going to load these "long" to account for the long throat. Must have forgot.

Michel
 
A 50gr charge of RE#22 and a 160gr is screaming and goes into one ragged hole with my BRNO 21H as well as 49gr Win 760/140gr............all with mag primers........wouldn't try these in a old 93-95 mauser though.................Harold
 
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