Does old powder cause this decrease in velocity?

[Gar Guru]

Have an old metal 1 lb can of IMR 4198 that I recently loaded some .223 with 55 gr bullets. Hodgdon website said I should get 3000 fps but when I shot it my chrono said only 2400 fps. I shot some factory FMJ loads also and the POI was about 4 inches off from my handloads. The pricing on the can says $3.15 so it must be 40 years old. Powder smells good though.

 

[DJ Fergus]

I'm not sure about age of it affecting velocity. I have read posts & articles about people using imr4831 that was 30-40 years old with no issues. I do know that some powders will speed up if they are left out unsealed.

 

[243winxb]

The Hodgdon website is using a 24 inch barrel. Subtract about 35 fps per inch of shorter barrel.
I get around 2700 fps with a 14.5" bbl.

Whats your barrel length, gun?

 

[dgr416]

I know in alaska my powders froze and some ammo froze down to -60 .The shotgun shells were the worse the pellets bounced off of grouse .My 454 loafs that were accurate became patterns instead of groups.

 

[Pa Grizz]

When Dupont sold out to IMR I had a good supply .I believe it changed in the 80's.I use the old Dupont powder for hunting because I can get at least 100 FPS better with the old powder

 

[DJ Fergus]

When Dupont sold out to IMR I had a good supply .I believe it changed in the 80's.I use the old Dupont powder for hunting because I can get at least 100 FPS better with the old powder

Sounds like DuPont's old formula for 4831 was a little slower burning.