21" Carbine rate of twist?

[paulb257]

I have a Thompson Center 21" .223 barrel One hole fore end).  Anyone know what the rate of twist of the rifling is?  I want to use 60 grain Nosler partitions in it.  Any help would be great!

[Grumulkin]

The twist is 1:12.

[Czech_too]

The factory twist rate would be 1:12.  Based upon what I have read, this twist is not fast enough to stabilize bullets over 55 grains.  I haven't tried anything heavier than this myself so can't verify it, perhaps others can.
http://www.eabco.com/TwistRate.htm

Brian, in Ohio

[paulb257]

I appreciate the info!  If anyone out there has experience shooting 60 Grain bullets I liked to hear from you.

[Grumulkin]

Actually, I shoot 70 gr. Speer Semi-Spitzers in my T/C 222 Rem., 223 Rem. & 22-250 Rem. barrels with excellent results.

Stabilization depends more on bullet length than on weight.  The bullets most likely to stablize will be flat based as opposed to boat tail and will be the less pointy ones.

[Huntz]

Actually, I shoot 70 gr. Speer Semi-Spitzers in my T/C 222 Rem., 223 Rem. & 22-250 Rem. barrels with excellent results.

Stabilization depends more on bullet length than on weight.  The bullets most likely to stablize will be flat based as opposed to boat tail and will be the less pointy ones.

   I will second that statement!!!!!

[paulb257]

I appreciate the info.     Anyone else?

[Camp Cook]

I also have a T/C Contender carbine with a 21" factory tapered 223 barrel.

I have loaded 23.5grs H322 with 60gr Sierra Varminter HP's in it but velocity was so low that I decided not to use them any longer accuracy was only ok were these loads would cluster into 1 1/2" 300 yard 10 shot groups in my 1-9" Rem 700-P...

I load 55gr Trophy Bonded Bear Claws with 24grs H322 average velocity is 3050fps groups are 1 1/2" @ 100 yards.

My load of choice for this rifle is...

40gr V-Max 25.5grs H322 = 3440fps average velocity = unbelievably accurate load in this rifle and maybe the most accurate rifle/load combo of any rifle I own absolutely amazing I have gotten 300 yard 1 1/4" 3 shot groups with this combo.

I was at the rifle range yesterday and was shooting 1" - 2" rocks on the berms behind the 300 yard target stands I am using a Burris Compact 3-9X Ballistic reticle scope.

and yes the load works great on coyotes and I am heading out next week with this rifle/load to look for gophers...

[Camp Cook]

I went to the club today with the 223 rifle I posted in the pic above.

I am constantly amazed at the accuracy of this little rifle with the 40gr Hornady V-Max bullets @ 3440fps loads .

The scope on this barrel is a Burris Mini 3-9X ballistic plex which has the regular duplex reticle then 3 small dot on the bottom post.

The top 2 shots are with the 2nd dot down held at almost the exact elevation of the hits and the 3 shot group is with the 2nd dot held on the red dot.

All I can say is this is an amazing little rifle...