Well, I ran the Van Horn barrel through the paces again this morning, and the 15" 7TCU barrel really showed its preference for the Sierra 130 grain SIngle SHot Pistol bullet. I just kept working up as usual and keeping tabs of groups. At 28.5 grains of H-335, the accuracy of 2 groups averaged right at a half-inch. So I decided to clock the load. Avg. for 3 shots was 2311 fps -- and this is a velocity I have never reached with any previous 7 TCU. Thinking this might have been chronograph error, I broke out the Pact, and this time, the avg. was 2308 fps.

The action opened with ease, the cases even had some remaining soot on the necks, primer pockets are still fairly tight and there's no indication of an impression from the rimfire pin, something that is accepted as an indicator that safe pressures in the Contender have been surpassed.

I do know that custom barrels reach higher velocities than factory TC barrels, but even with this realization, 2300+ fps with a 130 in a 7 TCU seems too good to be true. I guess I should be thrilled, but that high of a velocity results in some concerns in the back of my mind, even though everything seems to indicate it is a perfectly safe load.

Your thoughts???

Bobby,
An extra inch of barrel, proper finish on the chamber, custom barrel on top of that, and depending on the twist(?) you will sometimes surpass expectations without going excessive on pressure. Enjoy!
Sounds like you may have a "hummer" barrel.
xphunter

bobby,,now there's ya a deer huntin load !!
im glad your barrel worked out so well.
buckweet

I'd say that you simply have a good barrel there with "normal" land and groove widths unlike the factory barrels.

That plus a few things like and extra inch of barrel seem to cumulatively be giving you some great performance. I also wouldn't doubt your experience developing loads safely.

You also have the added margin with the 223 diameter case in the Contender from a safety standpoint.

BTW, In my Wolfe Wildcats book, it shows an article by Layne Simpson getting about 2240 FPS with a 130 Speer Spitzer out of a 14" factory barrel and N201 powder. You are not too far off from that velocity-wise.



[ 08-10-2002, 01:31: Message edited by: Headstamp ]

Bobby, I know you like H-335, but about the only powder I have used in the 7 TCU is AA 2015BR.
I couldn't find all of my load data on the 130 SSP's. The bit I did find had the Sierra 130's clocked at 2180 fps, with the AA 2015BR around 26.0 grains. Max load in AA book is 28.0 grains.
I see some H-335 in my future though. Last time I was at the range talked to a couple of fellows in the club, one of them had ten 1 pound jugs that he didn't have any use for any more $5 a pound. I had a particular XP in mind that I figured would digest it pretty well. I have it in the factory stock now, the other one is in the "body shop" the guys are wanting to paint it red with yellow flames!! I have a 5X Burris on it now. Have to work Sat. AM but will get to the range in the PM to see how many of the "misses" you have shot out of it.
Jeff

Thanks for the wise words, fellows. Guess I just needed to hear it from you guys even though all indicators pointed toward it being a safe, sound load.

Jeff-
The S14s in 7 TCU I had, with one exception, struggled to get around 2200 fps with 120s. The "fast" barrel did around 2370 using H335 with the Hornady 120 grain SSP/tipped. So that Sierra figure is pretty close when it comes to factory tubes.

So I am quite pleased with the Van Horn velocity.

Yes, you should give that 6mm-.223 a dose of H335 under some 80 grain Sierra SSPs and let 'er fly. I think I mentioned the bore was due for a cleaning, but I never got to it before sending it. One good thing about it, though, is that accuracy really never really suffered with a dirty bore. Guess it's more of a "maintenence" thing as I like to clean the smaller medium-velocity calibers every 80-100 rounds.

Let me know if the misses have been shot out...

Bobby, FWIW, Nosler #3 Manual shows max velocities of: 2430 fps/RL 7/26.5 gr; 2410 fps/H322/28.5 gr; 2320 fps/IMR 4227/22.5 gr, and 2320 fps/RL 12/31.0 gr. This is w/ a 14" Lilja test barrel w/ 1/9" twist. It doesn't have loads for H335. Even shows max vel of 2290 and 2270 fps w/ 140 gr bullets. I initially thought your velocities were kinda high, but on further reflection, I guess not. Gary T.

Bobby,
I guess this is what you get from a well made barrel. That's great to hear that the Van Horn barrels are truly good ones. I get to work with mine in a couple of weeks.