• Watch Out for Scammers!

    We've now added a color code for all accounts. Orange accounts are new members, Blue are full members, and Green are Supporters. If you get a message about a sale from an orange account, make sure you pay attention before sending any money!

Est velocity loss 308 win

1shot2kill

Gunny Sergeant
Full Member
Minuteman
Dec 9, 2008
1,323
9
40
north dakota
i am going to have my 24" barrel shortened to 20" has anyone here done this and chronoed the results
155 scenar
45.5 gr varget
lapua case
cci primer
 
Re: Est velocity loss 308 win

that has been covered in depth - someone cut, crowned and chronoed a 308 in 1 inch steps - think I remember 20 FPS/ inch

try some google search
 
Re: Est velocity loss 308 win

Go for it. I bet the handier rifle will outweigh any velocity loss you will have.
 
Re: Est velocity loss 308 win

I would guess a 100 FPS loss. I see a 200 FPS difference between my 24" and my 16.5" 308 with the same loads.

I still prefer a shorter barrel with a 308, velocity be damned.
 
Re: Est velocity loss 308 win

I have 16", 20" and 24" 308s and my loads look like sort of like this:

43 varget LC brass 175SMK

16" = 2450
20" = 2530
24" = 2600ish

My thinking is either have a 16" or a 24". The 20" isn't as compact as the 16" and can't reach out as far as the 24" so I'm not sure what the point of it is.
 
Re: Est velocity loss 308 win

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BCP</div><div class="ubbcode-body">I have 16", 20" and 24" 308s and my loads look like sort of like this:

43 varget LC brass 175SMK

16" = 2450
20" = 2530
24" = 2600ish

My thinking is either have a 16" or a 24". The 20" isn't as compact as the 16" and can't reach out as far as the 24" so I'm not sure what the point of it is. </div></div>

so that 20 FPS/inch is right there
 
Re: Est velocity loss 308 win

ok thanks guys looks like i will go for the 20" if im not going to loose much
 
Re: Est velocity loss 308 win

I have 2 Remington 308 5Rs one is the 20" inch and the other is 24".

I know that they are 2 differnt rifles but you would think them to be pretty close.

The 24" runs 178s @ about 2720, and the 20" runs the same load @ 2690. The 20 seems more accurate. But again its two different guns and other factors may play a part.
 
Re: Est velocity loss 308 win

I had always heard 20-25 fps per inch the barrel is shortened. But even this can vary. Depending on the powder, if the barrel is so long that the powder gasses aren't expanding enough, the additional length and drag against the inside of the barrel can actually begin to slow the velocity.

The information above is consistent with all the stuff I have read in various articles over the past 20 years.
 
Re: Est velocity loss 308 win

I had a .300 Wby that I shortened from 26 to 22. Lost 350 fps. Dumbass that I was! Varies with the rifle.