PRB Ballistics

[deerstalkert]

just noticed i put in every thing but the ball size. this box of Hornady's swaged mic at .489 so with the thinner patch they almost fall into the barrel. if'n it don't rain tomorrow i am going to shoot for accuracy if i can find more caps! down to stems and seeds!

 

[Crane Senior]

So I never shot any muzzleloader over a cronygraph so today I fired 5 round balls from my Lyman GPR .54 caliber thru my crony it was most interesting. Each round fired got a little faster. The load was Speer .530 RB .18 patch 90 grains of 3F Goex powder first shot was 1610 FPS
1660 FPS
1683 FPS
1707 FPS
1739 FPS
I also fired 4 of the same loads thru my T/C renegade .54 26” barrel
1550 FPS
1636 FPS
1682 FPS
1537 FPS
I fired 5 rounds but the sun was getting low so last shot didn’t read on the crony extreme spread was a lot more than the Lyman. The longer barrel makes a difference

I chronographed my Pedersoli .50 cal Hawken (brought through Cabelas). The barrel is 1:48 twist, .495 ball, .010 linen patch using mink oil. I used 67 gr of 2F Goex and got 1410 FPS. Not bad, better than a 45ACP. I didn’t try an 80 or 90 gr load but may in the future for grins.

 

[Santa Fe]

I chronographed my Pedersoli .50 cal Hawken (brought through Cabelas). The barrel is 1:48 twist, .495 ball, .010 linen patch using mink oil. I used 67 gr of 2F Goex and got 1410 FPS. Not bad, better than a 45ACP. I didn’t try an 80 or 90 gr load but may in the future for grins.

28” barrel??

 

[Santa Fe]

Weather looks cold and wet for next 3 days so probably be Thursday before I can burn more powder.

 

[Crane Senior]

28” barrel??

Yes

 

[Santa Fe]

Well the sun was a shinin this afternoon so I got all set up for another round of ballistic testing and a dog gone gust of wind blew my crony over and busted it all ta pieces I’ll have target some new parts

 

[deerstalkert]

busted is busted i guess, but i usually bust mine with a 45-50 caliber bullet or ball!

 

[Santa Fe]

So while here might as well burn some powder. 5 shots 90 grains 2f Goex .530 RB .18 patch swabbed between shots From 100 yards Not very impressive lower left was the first shot. Definitely need some practice before Deer season

 

[Santa Fe]

Well I finally got new parts for my chronograph so I thought I’d resurrect this thread. So the .530 ball and .018 patch was really hard to load after a couple of shots and not very accurate. So I thought I’d try .535 ball and .018 patch and wow it actually loaded easier and grouped a lot tighter. 3 shots from 100 yards

 

[Rifleman1776]

A barely damp thin patch to ride over the fouling on the down stroke and bunch up and pull the fouling out on the way out.

Amen, Bro. Emphasis on "barely damp".

 

[hanshi]

Velocity increases are not always linear as powder charges increase. I don't chronograph often and then it's usually just to satisfy my curiosity about a favorite load. Among changes affecting velocity is the patch thickness. My chrono results are often merely scribbled on scratch paper then often lost or misplaced; many times I can't even read my own writing. A good example of odd speed increases is a couple of sessions chronographing a .40 X 38" X "B" wgt barrel. The first session was with pillow ticking patches (.015"?) lubed with Hoppes BP Lube. Second is mattress ticking patches (.018"-.019"?). Results below. (FWIW)
Powder is Goex 3F

Charge Ave. Vel. SD Comments
30 grains 1371 20
35 grns 1449 18
40 grns 1678 5 (a favorite load)
60 grns 1848 17 (another favorite)

Going from 30 to 35 grains (78fps) gives 15.6 fps per grain. Going from 35 to 40 grains (229 fps for a 5 grain increase) gives 45.8 fps per grain.
going from 40 grains to 60 grains (170 fps) gives 34 fps per grain.

Changing to Mattress ticking (.018" to .019"?)

Charge Ave. Vel. SD ES
40 grains 1658 31 fps (favorite)
60 grains 2137 16 (favorite)

479 fps 40 grns to 60 grns or 24 fps per grain. My current patches are from drop-cloth cotton canvas
(.024") - occasionally denim, cotton canvas duck or mattress ticking for particular guns.

 

[Santa Fe]

Hanshi that’s good information. Before I chronograph I had no idea black powder could drive a bullet that fast

 

[Santa Fe]

Well my plan for today was to get out the crony and shoot a few loads over it .But the wind was blowing so strong I decided not to take a chance on it blowing over my crony again. Hopefully later this week I can get out there and burn some powder

 

[Dirty Mike]

I got 1680 with my tc big boar 58 .570 ball .15 patch 100 grn 777 2f
Then shot a 615 grn conicals over 100 grn 777 and got 1160

 

[Santa Fe]

Wow .570 ball weight is 279 grains At 1680 FPS that’s a serious thump

 

[Santa Fe]

Well I finally got to the range this weekend I shot a 95 grn 3 f powder .535 rd with an .018 patch the 4th and 5th balls were really tuff to load
1674 FPS
1704
1786
1689
1778
These next 5 shots I swabed between loads with a damp patch
1707 FPS
1763
1675
1736
1759
I fired one .535 rb without a patch
Just for the heck of it.
1673 FPS no doubt the accuracy would stink but at close range it’s deadly

 

[Santa Fe]

Ok 5 more shots all my loads are with GOEX powder and Lyman GPR .54 cal. 1-60 twist
95 grn 3f .535 rb .015 patch these are a lot easier to ram down the barrel I did not swab between shots
1570 FPS
1615
1647
1740
1685
I did not test for accuracy I will do that at a later date

 

[Frontier's]

The OP has some very horrible variants going on. Terrible spread from one shot to the next.

 

[necchi]

Can I ask why your concerned about velocity? I mean with all the chrono testing,,(?)
In your own words your not testing for accuracy at this point.
I ask because these ML's are a different creature than the CF's, because of bore fouling,, and the operators/shooters response to it.
Each shooter has his own "regime" of patch, lube and bore condition resulting from his own actions.
Like CF, ideal conditions improve with consistency,, aka; making everything the same with each shot.
Don't get me wrong, knowing an average velocity with all SD considered is a good thing while learning the distant and terminal ballistics of the rifle, but for me it's always been a result found "after" the accurate load is developed.

 

[Loyalist Dave]

The OP has some very horrible variants going on. Terrible spread from one shot to the next.

This is why for the folks who are really interested*, we should all chrono our loads, and note the brand, granulation, and the lot number.

A powder-lot might have an odd formulation, or it may react to high moisture situation if depending on the circumstances...
The measure may not be well calibrated,
perhaps for some reason the loads settled within the measure in an inconsistent manner,
What was done during swabbing may have a different impact on MV than not swabbing at all
Pressure on seating the patched ball also has an impact, as well as what type of lube and how much lube.

* Some folks just load, aim, fire and get a good group at their preferred hunting distances, and the deer drop, so are not concerned,
Some folks are merely curious as to what is going on, but they don't intend on changing anything.

LD