Chronographed my in-line ML

guntech59guntech59 Member Posts: 23,193 ✭✭✭
2 pellets of Pyrodex and a 245 gr Powerbelt got me a three shot average of 1225 fps at 12 feet.

I thought it would be around 1500 fps.

I am not concerned, as it gives me 2" groups at 100 yards, but I am surprised.


  • Okie743Okie743 Member Posts: 1,975 ✭✭✭
    edited November -1
    What is your caliber and gun model and barrel length??

    I now use 2F triple 7 (70-80gr) and get around 1500-1900 from a 26-28 inch 50 caliber barrel and a 300 gr Hornady XTP/mag bullet, but first I go for consistent accuracy before going to the chrony. Triple 7 burns about 10% hotter than pyrodex or black powder and stores real well if stored inside in a controlled environment of approx. 40 to 80 degrees F. I have some that is 5 years old and still ignites good. (use 209's with the triple 7, anything less for ignition and ignition is not consistent.
    Anything over 80gr of triple 7 in a 50 cal will results in a flyer every once in awhile and 60 to 70 gr max in a 54 caliber.
    I also have a 54 cal and it's velocity is about what you indicate and using jacketed pistol bullets (50 cal bullet) and a 54 cal sabot. I think the bullet is a speer 50 cal.

    Limit your shots to around 100 yards max and you won't have any problems taking deer sized game at your and my vel's listed above. Do not believe the 3-50gr pellets and 300 yard magnum BS you see on TV for Black powder guns.
    A very fast bullet (and lots of noise and smoke) not hitting the intended target does not do anything for me nor the animal.

    Another thought: If it's a 50 caliber try a 45 caliber bullet and a 50 cal sabot. (the power belt bullet usually does not fit real snug in the bore and you might be getting some blowby which would result in loss of velocity.

    When testing a load I take care and not get the barrel hot and keep the sabot out of direct sunshine if in a plastic bag. The colder a sabot the better the accuracy. (seals better) The tighter a sabot fits the better the accuracy will be in a bore cleaned with a bore brush before loading the saboted bullet. I clean the bore before each shot with a patch around a correct caliber bore BRUSH. (ignor the BS about some powders not fouling the bore and upsetting accuracy) Not a jag because jags have a tendency to hang in the bore. I do fire a fouling shot (and I use junk type bullets that I've accumulated that don't group well for the fouling shot) when I first go to the range so as to burn the grease out of the barrel.
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