I'm thinking about developing a load using a 120 TTSX out of my T3 SL 7mm-08. I've heard the TTSX performs best when driven fast. What muzzle velocity should I try to get for best bullet performance?



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Anything around 2950 fps would be my goal and should be very easy to achieve.

http://www.barnesbullets.com/files/2014/11/7mm-08RemingtonV6.pdf

This will get you to ~ 300 yards with an impact velocity of ~2300 fps, which I regard as ample.

This is just my approach of moderate loading in regards to enough impact velocity at realistic ranges.

Others may have more up to date ideas...

Big game and you can likely get close to 3100. Run it as fast as accurate -

For Barnes bullets, optimum velocity is as fast as you can drive it accurately and safely.

Yep, I drive'em fast ,no matter the chambering.

I've seen them impact moose at 3600+fps (obvious from more case capacity than a 7/08) and perform perfectly. You can't push them too fast IME, and I've tried... You should be able to make 3100+ out of a 7mm-08.

Barnes is showing 3050 using a 24" barrel with several powders.
http://barnesbullets.com/files/2014/11/7mm-08RemingtonV6.pdf

In their #4 manual they list 3100+ with several as well.

Barnes' loads are a little pessimistic. 44 gr. of RL 15, a F210 primer, in Remington brass averages in the high 3000's with good accuracy. That's out of a 22" barrel Montana. About the same out of a 22" Cooper. I'm still playing with Big Game and getting over 3100 fps with 50.0 gr. but I'm not finished working on this load (OAL trials) in my Montana. As always, I worked up to those loads in my rifles, others should do likewise.

The 120 TTSX shot well from my 84 at 3000 fps via Big Game. At the time I was also shooting the 120 NBT at 3100 fps with nearly the same charge. At 100, the TTSX was an inch higher than the NBT, but had similar POI out to 500y while using a Leupo w/LRD. The NBT was used for practice, and TTSX for hunting.

Have since switched to 162 AMAX.

I've run 120 cup core at 3050-3100 in two 21" guns, partial Sized RP 47/Varget - were safe in MY rifles - as always - Check manuals and work up.

I am shooting them at 3175fps out of a 24" Remington with excellent accuracy. This is with big game at 1 grain under the max in the nobler book for the 120gr bt.

I'm running 43 gr of RL15, haven't chrono, but they kill stuff dead. I'm guessing 3000 fps. 10 - 370yds with good results. Actually killed 2 does with one shot last yr at about 350 yds. Didn't mean to but it happens.

I'd run as hard as safely possible but for me 43 gr was more accurate than book max of 44.

43.5 grs of Varget pushes the 120 TTSX 3050 out of my 24" Hart!

Shot the same load in mine. 260 uses 40.5 gr of R-15 with a 120 TTSX at 2,900 but BC makes up for the velocity. Pretty much how the 7-08 got sold.

CFE-223, 2000MR, Big Game, can all reach well over 3100 fps safely in a 22-24" barrel. My X-Bolt loves 50.5 gr BG and WLR primers for about 3120 fps. This will be the backup gun for Hope and I both this year elk hunting.

It appears the important thing is impact velocity. From everything I've read at least 2000 fps at impact and a little faster doesn't hurt. The slower they are at the muzzle the sooner they drop below that 2000 fps threshold. So it depends on how far you want to shoot.

I rolled up some loads and ran them over my chrony. All loads at 2.805", using WLRM primers. Here's what I found:

43.0 gr Varget: 2959
44.0 gr Varget: 2974 (over max, not recommended)
45 gr Varget: 3030 flat primer (over max, not recommended)

47.5 gr CFE223: 3046 (over max, not recommended)

49.5 Big Game: 3039

22 7/16" barrel, T3 SL

Big Game is Unobtainium at present, I'll see what CFE does in the accuracy department.



P

2950 is what im getting for average with RL15 44 grns. 120 TTSX & 120 NBT. Montana in 708 22 brl. good enough for me.

What brass? WW holds about 1.5-2 gr more

Don't know the source of your load data, but Hodgdon lists 49.5 gr CFE-223, and 45.0 gr Varget with 120 gr Nosler BT.

I'd watch my chrony and work up carefully on that CFE load though. Your Ramshot BG load should be about 58kpsi according to Ramshot data. You should be safe with margin with all the loads you have listed.

The flat primer is interesting.

bludog

Using mag primers will have him using less powder as will the sticky nature of an all copper bullet.

I'm using TTSX, not BT. Bearing surfaces are different.



P

P- those speeds align with my findings on multiple 7-08's. Maybe we have slow clocks😜

BTW- I use 45grs of R15 for 2975 and call me happy....

I am wondering if a bit faster burning powder with the lighter bullet may help you in the velocity department. Have you tried a standard primer along with an increase in powder? Could be your gun likeS to be fed with the case more full of powder.

I'm at or slightly above max, so I'm not overly enthusiastic about going up in charge. Realistically, 50 fps isn't significant anyway.



P

As we know - Game has no crony. Just affects clicks or Kentucky windage -