58 velocity question

[brpc]

I am shooting a .570 PRB,.015 dry patch (dutch shoultz method) with 80gr 777 out of a 1/48, 26in Green Moutain Barrel. Can anyone tell me approximate velocity? Accuracy is very good.

 

[roundball]

I am shooting a .570 PRB,.015 dry patch (dutch shoultz method) with 80gr 777 out of a 1/48, 26in Green Moutain Barrel. Can anyone tell me approximate velocity? Accuracy is very good.

Maybe you can extrapolate from TC's Goex FFg load data:

80=1302fps
90=1373fps
100=1428fps
110=1519fps
120=1595fps

 

[Reskidmore]

brpc,

I had a fullstock Hawkins 36" barrel and using my Crony I got 1530fps .570 rb .015 patch and 85 gr 777. Just sold it to much to carry hunting in the hills.

Hope that helps.

Skids

 

[tcsmokepole]

With 70 grs. of 777 and a 570 roundball with a .10 patch I got 1516 f.p.s. out of my 26 inch barrel renegade. With 120 grs. of Goex 2F and the same patch-ball combination I get 1468 f.p.s.

 

[roundball]

I am shooting a .570 PRB,.015 dry patch (dutch shoultz method) with 80gr 777 out of a 1/48, 26in Green Moutain Barrel. Can anyone tell me approximate velocity? Accuracy is very good.

One more thing...Oxyoke wonderwads are supposed to boost velocity by making a better seal...I use them with all my hunting loads for all the benefits, not just increased velocity...so that might be something you could consider.

In fact, to try and get an even tighter seal & firewall, I use the next larger caliber size wads...ie: I use .62cal wonderwads in my .58cal GM barrel, .58cal wads in my .54, etc, etc...the patches essentially look like new when you pick them up off the ground

 

I just found my chronographed data for the .58 hawken I had. The barrel was 32" by 1 1/8" octagonal and Green River by make. The twist was 60". All velocities I've printed before were attempts to remember from 24 years ago and were low of what I actually got.
: 95gr. 2F C&H .575RB .020" Denim Bear Greased patch - 1,424fps.

:140gr. 2F C&H .575RB .020" Denim Spit 1,683fps

: " " " " " Bear grease 1,736fps

:160gr. " " " " Bear grease 1,867fps

:185gr. " " " " Bear grease 1,951fps

: The 140gr. charge became my favourite for a hunting charge due to it's exceptional acuracy out to 150yds.
: Although these sound high,
: Note - velocity vs pressure.
: Guns from .45 up show similar pressure with round balls for similar velocity. Therefore, the pressure of the top load I was using must have been less than 12,000 CUP, well within the strength of the rifle used & is in the range of maximum loads for Italian and Spanish rifles.
: GreenRiver Rifle Works lists working loads for their barrels as 140gr.2FC&H suggested load and 195gr.2FC&H as being maximum.
: This is considerably less than the 29,000PSI achieved with 100gr. RS Pyrodex with a 250gr. Sabot in a .50 cal muzzleloading rifle.