Home Forums Hunting & Shooting Ask The Gunwriters Superformance burning dirty

I am working a load with Superformance and 88gr ELDMs in my 1:8" 22-250.

With 36.9 gr and a F210M primer I get 2,933 fps and good accuracy, but the first 10 inches or so of the barrel are dirty with soot that looks like it had been sprayed and laid down in the barrel bottom by gravity.

It looked like it was loose, but would not move when shaking the barrel muzzle down. It cleaned very easily with a couple of patches with Bore Tech carbon remover.

I swapped to an RWS 5333 magnum primer and nothing changed: same speed, same accuracy, and same sooting in the barrel.

Would this powder, like Mule Deer has described with some sphericals, would need more pressure to burn cleanly?

What kind of speed would you consider a reasonable maximum with 88 ELDMs and Superfomance in the 22-250?

Thank you !

Alvaro

Wonder if someone with QL could hook you up with a couple projections to get you in the ballpark?

That would be fantastic, Beretz. I have QL, but an older version, and Superformance is not included.

I just put out a call to help Chamois. Maybe he will see the Bat Signal.

Alvaro,

I would try adding a little more powder.

The hunting load we use in our pair of 1-8 twist .22-250s (both with 22-inch barrels) is 41.0 Superformance with the 70-grain Hornady GMX, which gets 3300-3400 fps. Have never had the slightest indication of excessive pressure even in above-average temperatures.

This velocity converts to around 3100 fps with an 88-grain bullet, according to "The Rules" I worked up years ago--which I've generally found at as accurate as QL. I would add more powder and see what happens.

John

Seeing some info on quickload would be cool. I have a hard time going above book max (39.3 grains) listed for the 80gr Hornady ELD match bullet on a bullet that is 8 grains heavier. Maybe it's some magic bullet, but most times a heavier bullet requires a little less powder to stay in a safe range. It would be damn nice if Hornady would get off their azzes and do some testing with these bullets in the 22-250 and get some data out to us.

Thank you, John.

Please refresh me up on the rule regarding bullet weight vs speed in the same cartridge... I can't remember well if it was a 1/4 rule as well.

The speed is reduced at a 25% of the % increase in bullet weight pressure remaining constant?

In this case bullet weight is increased 25% from 70 to 88gr, so speed should come down 1/4 0f 25% or 6.25%
Your mid velocity of 3350fps - 6.25% = 3,140, or "around" the 3,100 you say.

To err on the safe side I will work up to 3,050 and see how it goes.

Kind regards to Eileen and you from Spain.

Alvaro

I will run the QL for you in a little bit this morning.

What is your barrel length?

Not QL but here ya go, exact seating depth and OAL will change the data some

Seems about right for JB's guess of 3050'ish if ran up to around 65K PSI.. Thanks for that Swifty.

Thank you, Swifty!
To what pressure does the GRT correlate 3,050 fps speed?
Alvaro

yep he's pretty dang close

That's not too shabby from the old 250 case... That bullet should float.

Yeah, he's "pretty dang close" at his recommended 41 grains? Ok.

If I'm reading that chart right, it looks like 38 was a little over max, as it says "ATTENTION OVERPRESSURE (this charge is dangerous, do not use!!)", even at 37.5 grains. There's a reason I did not go over 37.5gr in my testing. Unless I'm reading that chart wrong, you guys can correct me if I'm wrong. Thanks for doing the QL swifty. I appreciate it. Pretty much told me what I already knew, but it's good to see it in the QL.

BSA
I didn’t see MD’s prediction on charge, I was going on the 3050 @65,000 psi. But yes that’s an over pressure load at 38, 38.5 went 66K psi with only a 20-25 fps rise. 39 grains popped 70K psi with only 10-15fps rise.
Oh and that’s not QL, it’s Gordon’s Reloading Tool. Dang freebie. 😁

Addendum

41 grains predicted pressure 86K psi with 3340 fps

Great observation. Never used GRT.

I take good note of GRT's estimations, thanks everybody.
I will work up my current load of 36,9 and see how everything goes, powder residue included.
Will report before the end of the week.
Alvaro

PS: Swifty, John`s 41gr load was with the 18gr lighter 70gr GMX.

37 grains



41 grains