Experiences running 223 in F/TR

[Ned Ludd]

Is this the correct uni-throater for the .223?
http://pacifictoolandgauge.com/thro...3-specify_reamer_caliber-22_cal_223_cal_556mm

I'm almost positive this is the correct one, but a call to PTG would confirm without any doubt.

 

[Mozella]

........ snip............ I shoot the Berger 90gr VLDs tipped with a Whidden tipping die seated just touching the lands (testing proved that was the best for this rig). My CBTO is 3.05". ......... snip.........

I'm guessing you meant to say your CBTO is 2.05", right? Either that or your 90's are a lot longer than mine which give me a CBTO of 2.102" with a .010 jam.

 

[ej3rd]

I'm guessing you meant to say your CBTO is 2.05", right? Either that or your 90's are a lot longer than mine which give me a CBTO of 2.102" with a .010 jam.

My CBTO is 77.4mm which I think converts to 3.05". I worked for the Honda Motor Company for 23 years so all my measuring is metric. I have to use a .308 ammo box as the rounds are way too long for a .223 one.

 

[ej3rd]

I'm guessing you meant to say your CBTO is 2.05", right? Either that or your 90's are a lot longer than mine which give me a CBTO of 2.102" with a .010 jam.

I just had a thought, that CBTO measurement waswith the Sinclair tool in place. It's my reference measurement not the actual. Sorry about the confusion.

 

[Hengehold]

The following were all shot in the last 13 months using a .223/90 VLDs:

Needless to say, I'm pretty pleased with the .223/90 VLD combo.

As far as being difficult to load, search through this forum using the query "90 VLDs". You will find more good info than you can shake a stick at regarding how to get them to shoot.

The short version is, you want the 223 Rem ISSF reamer from PTG that has 0.169" freebore. Your COAL will [roughly] be in the 2.630" to 2.650" range. Using a 30" 7-twist barrel ( a 6.5-twist might be even a tick better, but not absolutely necessary), shoot for approximately 2815-2825 fps with Varget and Lapua brass, 2840-2850 fps with H4895 and Lapua brass. Brass life with Varget is pretty reasonable. Brass life with H4895 will be 3-4 firings. The real key is seating depth. Most find about .010" into the lands is optimal. A few have found about .005" off the lands (fairly close to touching) works best, and the fewest of the few (including myself) are jumping them about .015" to .020". So there you have the chamber, target velocity ranges with two commonly-used powders, and the most likely seating depth regions to test. Short of having someone else load and test them, it doesn't get much easier than that.

Final note - with the 0.169 freebore chamber, you can still shoot 80 gr bullets such as the 80.5 Fullbore very well, although they will be seated fairly far out in the neck. The opposite is not true; i.e. if you try to load the 90s in a chamber optimized for the 80 gr bullets with something like .100" to .130" freebore, you will be giving up way too much velocity (and effectively, the major advantage of using the 90s). There is nothing wrong with using the 80 gr bullets in F-TR. However, even though you can push them faster than the 90s, the BC deficit simply cannot be made up by increased velocity. At 600 yds, the 90 VLDs at 2850 fps will keep up with (or shoot inside) most any typical 185 Juggernaut loads in the .308. They will be at a disadvantage against the 200+ gr offerings in 30 cal, but that shouldn't be a big surprise. The almost complete lack of recoil makes the precision possible with a .223/90 VLD combo insanely good. When the wind comes up, you have to be much, much better at wind calls when using 80 gr bullets in the .223.

Is there any particular reason why you opted to go with a 1-7 twist rather than a 1-6.5 twist? I believe a 1-6.5 is recommended for the 90gr bullets.

Thanks,
-T

 

[Ned Ludd]

To me it's really a tossup. With a 7-twist barrel, you're probably giving up something like 3% of the "theoretical" maximal BC. With a 6.5 twist, you're putting a little more force on the bullet jacket and might get a tick less velocity at a given pressure. I seem to recall about that time I was going through Bryan Litz's 1st book, which emphasized the use of a twist rate sufficient to achieve a minimum Sg of 1.4 or greater. At the time I actually ordered that particular rifle built, the notion of having Sg of 1.5 or greater to obtain full BC may not have yet been common knowledge, it's a few years ago and frankly I don't recall exactly what I was thinking, if at all . In any event, I just recently had another one built using a 6.8 twist. It's just enough to achieve full BC where I currently live and shoot most often. Having said that, there is no reason a 6.5 twist shouldn't work just fine.

 

[cmillard]

i think laurie Holland successfully used a 7" twist with 90s out to 1200 yards in competition, do a little searching or send him a PM

 

[USMCDOC]

i think laurie Holland successfully used a 7" twist with 90s out to 1200 yards in competition, do a little searching or send him a PM

Yes he has.. as i have used a 7.2 twist to 1K with great success!

 

[skiutah02]

I started a new thread yesterday that in part addresses the OP topic. Search "Ugly gun" As for the 223 at 1000, specifically, I talk about my use of the 223 at this years LR Fclass Nationals in a different thread. You can find that tidbit if you search "Wicked BC" and find the post about the newly released 200.20x. Drew