7mm-TCU and 200meter Rams

[lead Foot]

Just bought an old 10"Thompson - Center in 7mm TCU. It's in good condition and very happy with it. I loaded it with 18grs of AR2207 (same as H4198) behind an RCBS 7mm-145-sil @ 1552fps (802ftlbs). Wobbling out of the 4x4 window I put five shots into .7" 50meters, most empressed. Never had a handgun shoot that well. We have a zone shoot at the end of the month and don't know if this load will knock the 200meter rams over. We have a cast rifle match on the same silhouettes and I use a 7mm08 with 130gr lee boolit. At 1775fps has trouble knocking the rams over ~ you have to hit em' high. Your thoughts please ~ the load is so accuate, do you think I have to up the load or she'll be right.
Thanks Lead foot;


http://i994.photobucket.com/albums/af64/MrLeadfoot/2010_0912alt0001.jpg

[blaser.306]

I also shoot a 10" 7 tcu and in my oppinion this is one time that boollit weight will be your friend ! If you have a load with good accuracy potential and you can do your part (putting them where they need to go ) the extra retained energy from 15 gr. more lead should do the trick . I also shoot a 15" wichita sillouette pistol in 7/08 and it seems to have no problems knocking the rams over @200 meters , it puts craters into the T-1 chickens with hard cast boolits though !!!

[44man]

Just bought an old 10"Thompson - Center in 7mm TCU. It's in good condition and very happy with it. I loaded it with 18grs of AR2207 (same as H4198) behind an RCBS 7mm-145-sil @ 1552fps (802ftlbs). Wobbling out of the 4x4 window I put five shots into .7" 50meters, most empressed. Never had a handgun shoot that well. We have a zone shoot at the end of the month and don't know if this load will knock the 200meter rams over. We have a cast rifle match on the same silhouettes and I use a 7mm08 with 130gr lee boolit. At 1775fps has trouble knocking the rams over ~ you have to hit em' high. Your thoughts please ~ the load is so accuate, do you think I have to up the load or she'll be right.
Thanks Lead foot;


http://i994.photobucket.com/albums/af64/MrLeadfoot/2010_0912alt0001.jpg
I have shot many TC's and found that the 7TCU is one of the very best. A friend has one and we were plinking at cans and plastic bottles at 200 yards. I was shooting Creedmore and he seen a mouse run under a small stone on the berm. After he told me where, I shot the stone and the mouse went 20 feet in the air.
I will mail him and get his load.

[fourarmed]

Your 7 TC/U load has slightly less momentum than your 7-08 load AT THE MUZZLE. The extra sectional density will make the heavier bullet lose less velocity at 200 m, which will partially offset the difference. If your rams are set according to the IHMSA topple rule, you shouldn't ring too many of them.

[lead Foot]

Thanks guys. I don't understand how sectional density works. But sounds like a better fourmula. I know foot pounds don't mean a hoot in knocking silhouettes over.I'm going to the range this morning for a little testing.:drinks:
:drinks:Lead foot

[GrizzLeeBear]

Actually, its MOMENTUM that knocks down sillywets, not sectional density or ft. lbs. I don't recall the formula, but bullet weight is much more important at increasing momentum than velocity. But fourarmed is correct that the better sectional density (and B.C.) of the heavier bullet will retain velocity better downrange. So, the heavier bullet allows you to put more momentum on the target by increasing BOTH bullet weight AND striking velocity. If your targets are set properly using IHMSA topple rule, your load should work just fine.

[fourarmed]

Momentum is mass times velocity, and in the non-metric system is measured in pound seconds. The formula is weight in grains times velocity in fps, divided by 224,000 to give the correct units. The momentum of your 7-08 load is 1.03 lb s at the muzzle. The 7 TC/U is producing 1.00 lb s. The rule of thumb is that it takes at least one pound second ON THE RAM to knock over a properly set ram.

[lead Foot]

Momentum is mass times velocity, and in the non-metric system is measured in pound seconds. The formula is weight in grains times velocity in fps, divided by 224,000 to give the correct units. The momentum of your 7-08 load is 1.03 lb s at the muzzle. The 7 TC/U is producing 1.00 lb s. The rule of thumb is that it takes at least one pound second ON THE RAM to knock over a properly set ram.

Thanks for the info ~ momentum is the way to go. Thanks for the formula. I did a test today. from a rest I hit ten rams in a row. Two did'nt fall. I up't the laod to 1630fps. All ten rams bit the dust ( using the IHMSA topple rule). I don't know how accuate the new load is, so i'll just use it for the rams until I have the time to sort it out.
Lead foot;

[DragoonDrake]

Lead foot,

I picked up a 14" 7tcu and am planning on using it for IHMSA with the same bullet. If you don't mind sharing, what is your load and alloy? Thanks

Adam

[44man]

I still have my MOA in 7BR and I used the Hornady 154 gr bullet with 18 gr of 4759. That gives me good velocity and I never lost a single target. You are in the ballpark.
This MOA is funny because it is rifled for heavy bullets and shoots from 154 to 175 gr like lasers. Since I quit IHMSA I want it for deer with a 120 gr SSP bullet but could never do more then spray a 50 meter target. I tried every powder and the only thing left was Varget. I called Hodgdon and they said it would not work, too slow.
Heck with it so I worked loads and the light bullet shoots like a house afire. I use 32.5 gr of Varget for 2175 fps.
My 7R uses the 154 gr Hornady with 18.4 gr of 4759 for 1633 fps and it never failed to topple steel.
My 120 gr deer load is also Varget, 34.5 gr and is deadly.
Don't let the little 7's fool you, they are just great to work with.

[45r]

I used rem 150's in my 7tcu because they were cheap and they worked.Haven't shot competition in a long time so can't remember the powder.I shoot sierra 130 SSP j-word for hunting with Vit-133.Does 1 to 2 inchs at a 100 yards.

[lead Foot]

Lead foot,

I picked up a 14" 7tcu and am planning on using it for IHMSA with the same bullet. If you don't mind sharing, what is your load and alloy? Thanks

Adam

Best load so far is 18gr H4198 @ 1552.2fps. This load should be a bit quicker with the 14" barrel. 1600+ fps would be safer for silhouette rams, ok for the rest. My RCBS 7mm-145-sil is the best but my mould is out of round by a mile. The driving band measure's .283-.285 but shoots so well. Lead is 50/50 pure/lino + 3% tin.
Might try H4895 next. the guy I bought the gun of had 120gr jackets ~ blow a flame a foot long only 1500+ fps. Momentum is a good way to measure knock down power and easy to work out thanks to fourarmed.
Lead foot;

[DragoonDrake]

Thank you lead foot

[missionary5155]

Greetings
I shot a 7TCU for two years. The 145 bullet will knock rams flat if you get into the habit of hitting them at least half way up. I hade my 10 " sighted to be dead on the sights at 200 meters (so many clicks up) and then I always aimed 2/3 up on the body. Never lost a ram that way. I shot my 14" barrel the same way.
That was probably the most accurate handgun I ever owned also. For practice I would head shoot the chickens, pigs and turkeys. The pigs will do a neet spin on the stand if hit out towards the nose.

[44man]

Pete sent his loads and the 139 and 154 Hornady uses 25 gr of H335.
He uses the same load with the 160 gr Speer.