The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Single Shot Pistols What Rifling Twist for a 6mm T/CU ?Go | New | Find | Notify | Tools | Reply | |
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Both of my 6mm-.223s (an XP-100 which I sold to a forum member and my current 15" VVCG barrel)had 1:10 twists and group lighter bullets extremely accurately -- just as with the medium-weight 80-85 grain bullets. Within reason, I feel you can't overstablize a bullet, but you certainly can understabilize one. Especially considering the lower velocities you'll be operating at, I'd go with the 1:10 and never look back... | |||
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| <Fireball> |
Many LONG range shooters are now thinking that you cannot over stabilize a bullet. The new therory is that the faster you spin it the better....UNLESS the bullet is NOT of good quality or concentricity. Their is a website I seen that says the problem is some bullets are out of balance and can be only spun so fast and then get thrown out of wack. And in a handgun we do not get the smae velocity as in a rifle so the rate of SPIN leaving the barrel is slower ...so as to need a slightly higher twist rate. I am not sure but I think my next custom barrel will be of a VERY fast twist to try the theory. I feel there is Nothing to lose in a faster twist rate in a pistol from what I have read. Makes me wonder if this is why my 6BR barrel does not like the heavier bullets...Not enough twist for the velocity givin at the muzzle?? Fireball ![[Big Grin]](images/icons/grin.gif){kind=icon} | ||
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My two pfennig's worth. In the Contender with its limitations and with the limited capacity of the .223 Rem. case, I would suggest, from what I have seen, not going over about 70 to 75 gr. in order to keep the speed up. Remember energy goes up exponentially with velocity. The light bullets from handguns will give better penetration than what you might think. My bud, Howard, has zapped deer with 55 gr. 6mms from 18" barrels using the .225 Win case and gotten complete penetration of the chest, but I don't think it was through the shoulders, just rib cage. Granted, the 1-10" twist is the safest for all potential applications except 105/107 gr. match bullets, but for general use, we have come to the conclusion that the speed afforded by the slower twist, about 200 fps between equal barrels with one having a 1-10" twist and the other a 1-12" twist, adds so much more range and energy that it is the best way to go. We have yet to test 1-13" twist but think that it will probably prove to be optimum. Remember, ole Howard is zapping yotes and groundhogs at 400 yards plus with a Contender, and I dare say there are few of us here that have anywhere near the experience day in and day out that he does..... we can only dream about the amount of hunting he does. When he speaks, I listen. He says 70 gr. of 6mm bullet is plenty from a Contender. Deer in his area are not big deer, but I dare say that with decent placement of shots, 70 gr. is still plenty. I would lean toward a flatter trajectory afforded by the higher velocity the slower twist permits. Face it, making a good hit with a Contender handgun, especially in a small cal. like 6mm, is more critical. Range estimation/bullet drop get to be a real problem past about 200 yards with most of the common deer calibers. Mike | |||
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| <Fireball> |
remove [ 10-07-2002, 02:56: Message edited by: Fireball ] | ||
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I almost always agree with what Mike has to say, but on this one, I don't. I have used the lighter weight bullets in the little sixes and, through my experience over the years, have come to settle upon the 80 grain weight (namely the Sierra 80 grain SSP) as optimum for a do-it-all bullet. It may not be quite as spectacular on the smaller varmints, but it performs well nonetheless -- and when it comes to coyotes, exotics and smaller deer, there's NO comparison. The 80 grain Sierra opens sufficiently, does plenty of damage along the way and almost always leaves an exit, an important consideration to veteran hunters. And, the difference in trajectories between a 70 and 80 grain bullet are not going to be significant (check the charts for yourself). You can gain a little in trajectory in going to a 55, 58 or 60 grain bullet, but if anything larger than 'chucks or coyotes is on the agenda, I highly recommend against it. I have gone through bucketfuls of .223 brass for the little 6mms wildcats, and in my humble opinion, the 80 grain Sierra Single Shot Pistol bullet is the only projectile you'll ever need for hunting applications. | |||
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| <Fireball> |
quote:Is your 6TCU a Custom or factory barrel? What is the accuracy like with the 80 grain? Do you know the velocity?...What barrel length? I am really starting to want some of these smaller calibers. Sorry about all the questions fireball | ||
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Fireball-I've had 2 14" factory 6TCUS barrels (several years ago). I also burned lots of rounds through a 788 rifle with a full bull bbl. in 6-.223. I just sold my XP in 6-.223 (14" Shilen bbl)to a forum member (he just shot a 40x40 with it) and am currently shooting a 15" VVCG 6x45 (a 6-.223 by another name). The 14" TCU factory barrels always seemed to do best, accuracy-wise, around 2700-2750 fps with the 80 grain bullets, as did the XP. The VVCG barrel is currently doing just over 2700 fps, but I still have a bit more load development work to do with this one (groups have been fantastic, though). The TCU has a slight capacity edge over the standard 6-.223 case, but the difference in performance is negligible. H-335 has pretty much been my exclusive powder for the little sixes, though my current load in the VVCG barrel is with BenchMark. And, it shows lots of promise... As to accuracy, there's no trick to getting sub-1-inch groups at 200 yards on a rather regular basis. Even on a "bad" day, you can generally count on putting five into 1.25" or so from 200 yards. | |||
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Fireball, if you have or think the 7 TCU is user friendly you gotta try one of the 6 mm varieties, as the are better yet. My factory 6 TCU is a pretty good shooter, but have been switching around some loads for the 1/2 size IHMSA targets. It will shot the 55 BK's pretty well but they are a Long way from the lands and grooves and groups tend to go to crap past 150, 3-4", not good when your steel target is about the size of a small cat at 200 meters. I have shot some 100's thru it for 150 and 200 meter full size targets as the lighter bullets were running out of steam to knock them over. It didn't seem to like them very well as groups went into about4-5" which isn't bad but not good enough for the game I am playing. I think a crown job would help it some, but have thoughts on a rechamber to somthing like a 6x47 AI. Bobby is right on "NO TRICK" to get small groups out of the 6-223 XP. The first go round I used H335 with some 80 grain Speers and some Sierra 80 grain SSP's. I didn't have time to do much load development, so used the H335 as per Bobby's recomendations. I ran out and have not had a chance to get an more so went to the Sierre manual, their accuracy load was with 748 so used that for the time being, and seems to work all right as that was the load I used for the 40x40. I feel REAL bad for buying the XP from Bobby as I think the guy had shot all the "misses" out of it and didn't realize it! ![[Wink]](images/icons/wink.gif){kind=icon} ![[Razz]](images/icons/tongue.gif){kind=icon} On the twist issue of this thread, if I had the extra $$ laying around, I would like to try a 6x45 or a 6 TCU with the 1-7" or 1-8" twist to try some of the 107's or heavier bullets for paper punching way on out there. But for the hunting I couldn't say as have not been down that road with the 6 mm handgun rounds, YET, hope to change that in the near future. Jeff | |||
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I too have to add positive comments on the 6TCU. I just got my first from Dave Van Horn and right outa the box I am getting around 1" at 200 meters. Mine is a 1:10 which should shoot up to 100 grainers but the 70gr BK's from Sierra are great for 1/2 size sillywet. 1:10 is as fast as DVH offers since he does his own gun drilling and rifling. At some ranges it is fine for full size but not at my home range. I like it so much, my shooting partner just ordered one and he has a 6TCU Rampro! I am pushing 2500fps which is book max for the 70 grainers but have yet to have the cases fully form out, still rounded corners. Going to try heavier next. My $.02 Mr. DW | |||
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MR.DW-Your "book max" must be from Sierra, which is very conservative for this cartridge. The Hornady, Speer & Hodgdon data is more in line with the potential of the cartridge. | |||
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quote:Congrats Jeff! I would have liked to been there to see it, but other duties called. As an off-topic side note, I managed to get my name in the IHMSA paper yesterday as I got my first Field Pistol 60 (61 in fact). Looks like I'll see ya out at Tri-Co as mamma is gonna let me out of the house! | |||
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Bobby, I had heard next to nothing about the Sierra SSP 80 gr. bullet, but if it expands ok, that is what counts. I have not scoured the ballistics charts lately comparing 55 gr. to 80 gr., but have deferred to Howard's reports. You work for a living. Howard is retired, so he probably gets in a bit more shooting and hunting. His goal is to minimize range estimation errors/bullet drop while getting the most effect he can at 400 yards and more. I'd have thought the 55s would have dropped off in velocity too badly for those ranges, but he swears by them and swears they kill much better than 55 gr. .22s at the same speed. I'll pay more attention to that Sierra bullet now that you brought it up. Thanks, Mike | |||
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Mike- Check it out. You'll like it. Been using it since the 80s and have found nothing else that compares in the critical areas of terminal performance for the 6x45, 6 TCU, etc. If you want, I'll even send you a few to try for yourself. Just let me know... | |||
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mike ?? small deer in howards area ??? are you kidding ?? them puppys big enuff too take out a chevy GEO.. trust me on this... i know !!! buckweet | |||
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1-10 twist... my .257tcu is a V V barrel.. 16.5 1-10 twist with nosler 85 grain balistic tip's going bout half inch @ 100 just my 2 cents.. buckweet | |||
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Buckweet, Those SW MO armadillies can do some damage, too! There are some nice deer down there, but usually the northern MO deer are bigger, correct? I only had two years there in MO, so I defer to you and the Geo. What is the blue tongue like now? Still a problem? Ref. the twist rate, Howard was trying to milk all the fps he could get from a 6mm. Works for him, but I have to admit I was a bit goosey over the thought of the really light bullets on deer. Hard to argue with him.... success can be pretty compelling. Mike | |||
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quote:Thanks, Bobby. I'm not doing much shooting for recreation at all since moving up here and at present don't have anything set up for myself in 6mm. My personal "itch to scratch" is a .250 Imp. with a slow twist. What I should do is lean on Howard to try the SSP bullets, but I have a pretty good clue what kind of lecture I'll get from him! My concern has always been inadequate expansion with the heavier 6mm bullets, but you say that is not an issue with the SSP. Howard is sorta my test lab since he has quite a few of my barrels with a number of variations to test against, such as 1-10" twist v. 1-12," with the same chambers. The added velocity of the 1-12" twist and the way it performs way out there on yotes and groundhogs has prompted us to think the 1-13" is probably optimum. Gotta try it.... just because we can. The old boy just does too well to dismiss him. Next time around, I'll run the 80 gr. SSP past him, then duck. ![[Eek!]](images/icons/shocked.gif){kind=icon} Mike | |||
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Mike - That .250 savage would just about scratch my quarter bore itch too. Maybe the quarter would make a good first offering... Maybe in the next couple of weeks... HAHAHA :-) steve | |||
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I'm sawing and squaring blanks tomorrow. Hopefully there will be a few turned down also. Quarter bores? Plural. No comment. Mike | |||
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mike...your correct... the deer up here in my area,are a wee bit bigger,, but ther have been some that i've seen running the turnpike,n' up to saint looie,on I-44, monsters,!!! the one i hit down at noel mo..took out the hood n' front clip, busted everything,, buckweet p.s. quarter bores ??? yeah..im hooked.. | |||
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And I will confess that the one I saw at a check station up north, west of Hannibal, MO was bigger than the biggest muley I have ever seen. There are exceptions, no doubt. Mike | |||
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