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Muzz FPS calculation?

doublerack

doublerack

Active Member
I'm not that experienced with black power so I was wondering...
Does anyone know how to figure out approx how man FPS you're shooting out your muzz?
I wasn't sure if there was a conversion chart or a way to calculate it pretty easy.
 
Too many varaibles: What powder? What charge? What weight bullet? Powerbelt or Sabot/bullet combo?

Really need a chronograph. My guess is that if you are using a max charge of BP and a 300 grain bullet, you are going to be somewhere around 1,900 fps.
 
Hodgdon does not recommend three 50 grain pellets at their website .

MAXIMUM LOAD WARNING
45 and 50 CALIBER RIFLE:
45 Caliber Pellets come in one size: 50 grain
50 Caliber Pellets come in two (2) sizes:
50 grain volume equivalent which equals 50 grains of loose powder by volume.
30 grain volume equivalent which equals 30 grains of loose powder by volume.
The maximum load per shot should never exceed total Pellets containing more than
100 grains volume equivalent. That means, no more than:
45 Caliber 1) Two (2) 50 grain Pellets
2) Three (3) 44/45 caliber 30 grain
50 Caliber 1) Three (3) 30 grain Pellets, or
2) Two (2) 50 grain Pellets, or
3) One (1) 50 grain Pellet and one (1) 30 grain Pellet

50 CALIBER BULLET & SABOT PELLETS USED VELOCITY (FPS)
180 gr. Knight / Red Hot One 50 cal. / 50 gr. + One 50 cal. / 30 gr. 1792
180 gr. Knight / Red Hot Three 50 cal. / 30 gr. 1880
180 gr. Knight / Red Hot Two 50 cal. / 50 gr. 1984
240 gr. Hdy. XTP 50/44 One 50 cal. / 50 gr. + One 50 cal. / 30 gr. 1613
240 gr. Hdy. XTP 50/44 Three 50 cal. / 30 gr. 1691
240 gr. Hdy. XTP 50/44 Two 50 cal. / 50 gr. 1801
250 gr. Knight / Red Hot One 50 cal. / 50 gr. + One 50 cal. / 30 gr. 1602
250 gr. Knight / Red Hot Three 50 cal. / 30 gr. 1688
250 gr. Knight / Red Hot Two 50 cal. / 50 gr. 1793
250 gr. Hdy. SST 50/45 One 50 cal. / 50 gr. + One 50 cal. / 30 gr. 1600
250 gr. Hdy. SST 50/45 Three 50 cal. / 30 gr. 1670
250 gr. Hdy. SST 50/45 Two 50 cal. / 50 gr. 1785
260 gr. Speer/MMP Sabot One 50 cal. / 50gr. + One 50 cal. / 30 gr. 1576
260 gr. Speer/MMP Sabot Three 50 cal. / 30 gr. 1641
260 gr. Speer/MMP Sabot Two 50 cal. / 50 gr. 1737
300 gr. T/C PTX One 50 cal. / 50 gr. + One 50 cal. / 30 gr. 1480
300 gr. T/C PTX Three 50 cal. / 30 gr. 1546
300 gr. T/C PTX Two 50 cal. / 50 gr. 1641


I saw where the T7 "magnum" pellets (where two pellets appear to be about 120 grains of powder) launches the 250 grain bullet just over 2,000 fps. So I'm guessing three 50 grain pellets would add maybe 200 fps.

I'm not advocating shooting three pellets. I have zero experience with T7. Blah, blah, blah disclaimer.
 
That is interesting since TC and Nikon with the BDC retical advertize 150grain of T7 and 250gr Hdy SST to fall perfectly into their reticals at the given distances. ?
 
Probably a matter of liability, as they probably don't want you sliding three 50 grainers down the barrel of a family heirloom. I've heard of many people who shoot 150 grains of T7 in modern mzs. I've also read a few articles that question the steel of certain manufacturers barrels. One author has almost made a career writing about the lack of proper proof testing of barrels used in the muzzle loading industry. If you have a quality rifle, I'm guessing you should be ok.
 
This summer I was dinking around with my 45 caliber and this is what I found. I started off shooting 150 grains of Pistol powder, but only had 3 shots because I couldn't find the pellets for sale anywhere. Well naturally, I couldn't hold a group with the 1st 3 shots of the year, so I had a bottle of T7 powder, and pellets. I started off with a 100 grains of t7 powder and shot a few times and was right where I wanted it, about 3.5 inches high at 100 yards.

I then put the target out to 200 yards and shot three rounds and they were all about 8 inches low and about a 2 - 2.5 inch group.

I didn't like that much, so I put in 150 grains of pellets and shot 3 rounds into the 100 yard target, and they were all right with the 100 grain charge. I thought well, maybe the extra powder doesn't do much, which I knew it would just by the kick.

I stuck the target back out to 200 yards and shot 3 times. All 3 were about 3 inches below the bullseye. A whole 5 inches above the 100 grain charge of powder. Well thats where I wanted it so that is where I left it.

As Far as velocity goes, I have no clue. I always heard a 50 caliber muzz was approximately 2000-2200 fps with a 250grain bullet, and a 45 caliber was approx 2600fps with a 175grain bullet.

goodluck!!
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">That is interesting since TC and Nikon with the BDC retical advertize 150grain of T7 and 250gr Hdy SST to fall perfectly into their reticals at the given distances. ? </div></div>
Thats exactly why I'm shooting what I am.
 
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