Scratching my head: 7x57 load development

[FlyGuy]

I have sometimes gotten good 7x57 loads with IMR 4064, but USUALLY it all comes back around to 3031.

I've had excellent performance with 3031 using the lighter 7mm bullets, as well as 150gr bullets in .308.
Highly underrated powder IMHO.

 

[ZG47]

The original .220 Swift factory ammunition was loaded with IMR 3031 BUT the large rifle primer pockets had small rifle flash holes, in order to keep pressures down. You do what you have to, whilst waiting for the right product to enter full production.

 

[7x57Joe]

I've had excellent performance with 3031 using the lighter 7mm bullets, as well as 150gr bullets in .308.
Highly underrated powder IMHO.

IMR-3031 is also good with the heavier bullets and gives good accuracy. I've used it with 175 grain Winchester Power Point bullets getting 2350 fps from my 22" barreled M.98. No pressure signs and cases reloaded 8x.

 

[Rare Breed]

Interesting....I just finished reloading and shooting my 275 Rigby with my 175 grain Nosler Partitions. They clover leave like my 140 grains. The key I found was in COAL. My 140 grain was 2.83 and my 175 grain was 2.89. When you read any reloading manual, they recommend about 3.045 which did not group well at all for me.

 

[rookhawk]

Interesting....I just finished reloading and shooting my 275 Rigby with my 175 grain Nosler Partitions. They clover leave like my 140 grains. The key I found was in COAL. My 140 grain was 2.83 and my 175 grain was 2.89. When you read any reloading manual, they recommend about 3.045 which did not group well at all for me.

It all depends on throat length. I used a Hornady OAL gauge to figure out I was long throated. I the. Determined COAL.

Every rifle, YMMV.

 

[sgt_zim]

Unless I am much mistaken, 7x57 was designed to shoot a 173 gr RN. I don't know anything about Dakota rifles, but I do know that 2 other old cartridges originally designed for RN have freebore to spare - 9.3x62 and 6.5x55 Swedish.

Close the breech, drop in a .25" wooden dowel to the bolt face, spin it and inscribe a circle on it. Open the breech, drop a projectile down it, make sure the ogive is just kissing the lands, then re-insert the dowel until it just touches the meplat, inscribe another circle on the dowel. Measure the distance between them, then back off .02 or .03 from there.

I'm not really a betting man, but I'd bet you get a longer COAL than what the books say. Start near the bottom, work up in half grain increments until you see pressure signs, then back off a grain.

 

[rookhawk]

Good suggestions for the reader. I used a Hornady lock and load gauge and set the bullet seating depth perfect for my specific rifle. I won’t be adjusting my dies, primer, bullet, nor brass moving forward. The only thing I’m playing with now is powder type or powder charge. I’m going to test different RL15 loads. RL is a notoriously accurate powder. Others on this forum point out that IMR4350 may be better, no argument. In either case, I need to test for velocity and accuracy to decide if I find a perfect RL15 load or if I must try another powder.

What I will say is initial load is slow, but very accurate. I have higher velocity loads I must try. I suspect I will achieve perfection with a rl15 load. Had I to do it over again, I would have started with 4350.

 

[1dirthawker]

if you have a long throat, i suspect your velocities will be a bit short of your expectations. north forks are great bullets and they tend to create less engraving forces (pressure) you might need more powder (or a faster burning powder) to get the velocities you are looking for.

you seem to be an experienced reloader, so watch your primers and case head expansion and you will be fine. it seems you have a great cartridge/caliber and a great bullet. now all you need is to get the velocity you want, i suspect the accuracy will just happen.

good luck wth your project

 

[GuttormG]

What speeds do you get with factory loads vs what the maker claims?

Reloading manuals are just guides, they are accurate for the exact test-gun and conditions.

 

[sgt_zim]

Good suggestions for the reader. I used a Hornady lock and load gauge and set the bullet seating depth perfect for my specific rifle. I won’t be adjusting my dies, primer, bullet, nor brass moving forward. The only thing I’m playing with now is powder type or powder charge. I’m going to test different RL15 loads. RL is a notoriously accurate powder. Others on this forum point out that IMR4350 may be better, no argument. In either case, I need to test for velocity and accuracy to decide if I find a perfect RL15 load or if I must try another powder.

What I will say is initial load is slow, but very accurate. I have higher velocity loads I must try. I suspect I will achieve perfection with a rl15 load. Had I to do it over again, I would have started with 4350.

@1dirthawker has the right of it, I think.

I have a lock and load, but I quit using it. Measure 10x, I get 10 different measurements, and it wasn't as though they were different by only 1 or 2 thou on each measurement. I could live with that.

 

[Clodo Ferreira]

Hi rookhawk,

I am a 7x57 user, mostly with my handloads, since 1972.
First of all, I would check the distance from the lock face to the begining of the lands. Is the right and logical thing to do, in my opinion. I always like to know this in ALL my rifles.
In a hunting rifle I leave 1 mm, or not less than 0,5 mm of bullet free travel.
After many years of handloading for the GREAT 7mm Mauser I arrived at the same idea of John Barsness: aim at velocity levels with the right powders insted specific charges:

140 grs 2800 / 2850 f/s with any of the 4350.
150 grs 2750 / 2800 f/s same powders.
160 grs 2650 / 2700 f/s same powders AND R19.
175 grs 2600 f/s with R19 or R22.

So, with your bullet selected I would use any of the 4350 with a charge that reach 2600 or 2650 f/s. The pressures will be OK.
And you are done!
Waidmannsheil!

 

[Clodo Ferreira]

I forgot to mention: all my rifles have 60 cm, Aprox. 23,6 " barrel lenght.

 

[camperx]

RS62 is a nice mild powder in a 7x57. Even with 50gr it recoils less than my .308s despite them putting out lower muzzle velocities.

 

[FlyGuy]

RS62 is a nice mild powder in a 7x57. Even with 50gr it recoils less than my .308s despite them putting out lower muzzle velocities.

I wish we could get the RS powders here in SA

 

[Old3Toe]

After many years of handloading for the GREAT 7mm Mauser I arrived at the same idea of John Barsness: aim at velocity levels with the right powders insted specific charges:

140 grs 2800 / 2850 f/s with any of the 4350.
150 grs 2750 / 2800 f/s same powders.
160 grs 2650 / 2700 f/s same powders AND R19.
175 grs 2600 f/s with R19 or R22.

So, with your bullet selected I would use any of the 4350 with a charge that reach 2600 or 2650 f/s. The pressures will be OK.
And you are done!
Waidmannsheil!

Absolutely this ^^^

45.0 grains of H4350, 162g Hornady (AMAX/ELDM), Norma brass, and the bullet seated fully so the boat tail is just past the neck. Done.

This load gets +/- 2650 and excellent accuracy from all my 7x57s. The high bc cup-n-core bullet just works and has left nothing to be desired on large deer or elk.