Why loads so slow?

[Trey Veston]

Got an 8lb jug of IMR 4227 from my dad and loaded up some .45 Colt loads for my Henry Black rifle.

Used 22 grains and 250 grain Hornady XTP bullet.

Based on the Hogdon data, using just 20 grains of powder, fired from a 7.250" barrel, should get 1150 fps using the exact same bullet.

I fired mine out of a 16" barrel and got right around 1150 fps, using 2 extra grains of powder.

Max load is 24.6 grains and gets 1343 fps out of the same 7" barrel.

Why would my loads be so much slower? Shooting at 32 degrees? Crimp too severe? Henry barrel too tight?

Shot another load using 10.5 grains of Unique and got 1200 fps and great 1" groups. 4227 loads were 1 3/4" groups.

 

[ArchAngelCD]

The velocity stated in the manuals is reporting what they achieved. When they tested they did so under different conditions than you are in, a different lot of powder than you have and a different barrel than you used. The difference you saw is not all that different percentage wise than what they got. I have found that different manual will show a different velocity with the same bullet, powder and charge weight. Look at 6 sources and you will probably get 6 different velocities. (except for Lee which is a copy of others data) You are doing nothing wrong and there is no reason for concern unless your velocity exceeds the data by a large margin.

 

[35 Whelen]

IMR4227 is a very slow powder for a pistol cartridge. Make double sure you're using a heavy roll crimp.

35W

 

[JFrank]

Got an 8lb jug of IMR 4227 from my dad and loaded up some .45 Colt loads for my Henry Black rifle.

Used 22 grains and 250 grain Hornady XTP bullet.

Based on the Hogdon data, using just 20 grains of powder, fired from a 7.250" barrel, should get 1150 fps using the exact same bullet.

I fired mine out of a 16" barrel and got right around 1150 fps, using 2 extra grains of powder.

Max load is 24.6 grains and gets 1343 fps out of the same 7" barrel.

Why would my loads be so much slower? Shooting at 32 degrees? Crimp too severe? Henry barrel too tight?

Shot another load using 10.5 grains of Unique and got 1200 fps and great 1" groups. 4227 loads were 1 3/4" groups.

View attachment 1052493

View attachment 1052494

Weigh your charges carefully and record your own data, fps varies per lot number per altitude and per temp

 

[Blue68f100]

According to the tables I have IMR 4227 looses ~ 1.17 ft/sec/DegF. So you give up ~ 60 ft/sec just in temp change alone.

 

[AJC1]

Any small increase in moisture of the powder can make significant changes in velosity. Put a portion in a glass jar with some desiccant packs for a week and see if it changes.

 

[243winxb]

IMR 4227

Based on the Hogdon data, using just 20 grains of powder, fired from a 7.250" barrel, should get 1150 fps using the exact same bullet.

Your quoting H data but using IMR powder?
There may be as much as 10% difference in burn rate, from slowest to fastest lots.

Using a mag primer?