Thread: Velocity loss for chpping 7mm08 ?

Got a 22 inch 9.5 twist 7mm08.

How much speed will I loose by chopping off 4 inches to get it down 18 ?

What load, projectile and velocity are you using at the "preshorten" barrel length

Speer #1628 145gr BTSP, ADI 2208 40.08 gr, was doing 2660 fps

Tikka T3 7/08.

22.5" barrel - 140gr BT @ 2900fps using 43.5gr 2208, Winchester LR primer, FC brass.

20" suppressed barrel - 140gr BT @2745fps using 43.2gr 2208, Fed 210 LR primer, Lapua brass.

Note: The original load was shooting around 2810fps when the barrel was shortened and suppressed. The rifle is shooting a lot more consistent with the newer load.

Originally Posted by ebf

Speer #1628 145gr BTSP, ADI 2208 40.08 gr, was doing 2660 fps

At that powder charge i don't think you will lose as many fps as normal, its possible that with a different powder/charge weight you could keep that velocity

I will be honest and say i have very little experience with a 145g in a 7mm08, - I have tried/used every other projectile though.

30 to 40 FPS per inch.But could gain some more accuracy.

Originally Posted by 7mmsaum

At that powder charge i don't think you will lose as many fps as normal, its possible that with a different powder/charge weight you could keep that velocity

I will be honest and say i have very little experience with a 145g in a 7mm08, - I have tried/used every other projectile though.

Tx A

Do you mind explaining the reasoning behind your comment on the (lack of) speed loss ? Is it because the load is relatively mild, max @ 41.5 ?

On the ADI website it looked like 2208 gives a bit more speed than 2206H.

Any other powder suggestions for 18inch ?

Like I said to DAF yesterday, I am a staunch traditionalist in terms of projectile choice. SP for hunting (BT if I can get them) and SMK / HP type for long range target. Boring, but I trust them more than the fancy M&M plastic tips

Yes its the mild load which I'm only presuming isn't using the last two inches of barrel as much as a stiff load would.

QuickLoad calculates a loss of 120 ft/sec, though without inputting any of the particulars of your set-up 2660 is a little high from what is predicted. Also plugged 2206H in and QL supports what the ADI website is saying, MV of 2500 ft/sec for the same peak pressure from 18". RL17 would get you back above 2600 in the shortened barrel.

Thanks Puffin, have not seen you at Kaitoke for ages... You still shooting up there ?

My load was a 140gr corelokt 47.5gr 2209 doing 2720fps with a 22' barrel. Same load when chopped to 18" was 2515fps. I now use 45gr H335 and a 110gr TTSX, goes 3018fps from 18" barrel with a gunworks suppressor on.

Originally Posted by stug

My load was a 140gr corelokt 47.5gr 2209 doing 2720fps with a 22' barrel. Same load when chopped to 18" was 2515fps. I now use 45gr H335 and a 110gr TTSX, goes 3018fps from 18" barrel with a gunworks suppressor on.

Jikes, not keen on 200fps drop . H335 is around ADI 2206H ?

How far out would you be happy to shoot the 110gr TTSX on animals stug ?

I've only shot one deer with it so far. A red spiker approx 150 yds away. Was quartering away shot, went in behind the shoulder and exited out the throat. Two goats at 100 yds were both one shot kills. I'd be happy to 300 yds with it.

You will loose 50 fps an inch. I did in my 7/08 going from 22 to 18 inches. 50 grains of H414 gets around 2900 fps with the 120 BT.

Grab my 7mm ebf. Mines had a trim to 18. So long as you have a chrony you could have a test session.


Sent from the swamp