Help with 7TCU load problems

[nattyB]

:eek:  Holeemakkralandee!  Its been a while since I wuz on the forums an'it took me forever to finally figger out I needed to re-register. Anyways... hello again everyone!

I've been loading/forming 7tcu from 223 brass and the danged necks never come out as long as the specs say they are supposed to!!! It seems that ther isn't enough brass to make them long enough, even after fireforming. I didnt go out to the garage and actually get the measurements of the brass but it seems like the neck is like almost .07 or .08 short (as I remember). Has anyone else experienced this or is it just bad likker on my part!  I've considered forming from 222mag brass (longer necks) but cases are a bit more expensive. HELLLLLLLP!

[nattyB]

I got my dead butt out and measured things...OAL on a finished case is 1.729 and Hogdon manual reccomends a trim lgth of 1.740 and a oal of 1.749.  Thats only .02 short, not .06. but still considerably short....yes?....no?

[Nate C]

I wouldn't sweat it too much.   After you've fired 'em a few times you'll get your .02 back.

The main thing is headspacing...  

For your fireform loads you can headspace on the bullet itself, seated to just touch the rifling. (Pressures will be slightly elevated by seating the bullet to touch the lands, so use a starting, or reduced load).

For your 'regular' loads, personal opinions vary but I headspace on that tiny little shoulder.   I played around with the sizing die, adjusting slowly down until the action will just barely close.    Then for a OAL cartridge length I start with the bullet touching the lands, then back it off a few hundreths of an inch.

If it sounds complicated, then that's my fault for not explaining it better - its pretty straightforward when you get the hang of it.    

Nate C

[Old Syko]

Might be bad likker, but I doubt it since I ain't never had none go bad.  Recently sized and fireformed 500 new rounds from virgin Winchester 223 brass.  Once fireformed the brass averaged 1.744.  I use strictly virgin brass and don't anneal.  I seldom get a split neck as I hear so many talk about.  This batch I had none.  Made the mistake of trying to use single fired 223 brass once and the ones that survived being sized were all short as you mention.  Also tried 2 different brands of brass but split too many in the dies so I didn't bother trying to measure.  Havn't tried Remington brass so I don't know how it would work.  Besides, WW is readily available where I live.

Although I've never done it myself I understand that too light a fireforming load will cause the problem you mention due to the case not getting a proper seal and therefore not forming properly to the chamber.

By the way, if you think that likker has gone bad, send it down and I'll give it a proper test for ya. :shock:

[nattyB]

I,ve always prefered to headspace the same way you do Nate, but I've been loading 120gr Speer HP's and when I stretch that pill way out there t'meet the lands, it sure doesnt leave much'a the pill stuck inta the neck! I've always checked all'a my loads for concentricity and the lack of bullet/caseneck overlap kinda freaks me out. But I 'spose an extree shot o' drambuie will cure that. (sorree Syco...that's the GOOD likker, but I'll share wit'ya iff'n your up this way!)

I never considered that anealing/brass flow might be the problem. I'll try some new WW fodder, it's what I normall use on my other stuff. I just got a "deal" on a batch of surplus 223 and though I was quite a smartypants! go figger! I've also been meaning to try some other pills with different ogives (farther forward) so I could get a more concentric/stable launch. Any thoughts there? I'd really like to find some good results with somethin' in the lower weight end, mebbe even the 100 grainers.

[Nate C]

I strongly agree with using new (unfired) 223 brass to start out with.   I have tried 1x fired 223 brass and the difference between that and the new stuff is significant.   I also don't anneal and rarely get neck splits ( <1 per 200rnds).

Regarding 120's..  Do you have access to a chrony?   As long as you are getting consistent shot-to-shot velocities (and you can't twist the bullets with your hand when they are seated) then you may be suprised at how little purchase you need.  Bottom line of course is what does your bbl like.

For comparison, I know everyone's chamber could be different, but my last 2 factory tc bbls both liked the 139g Hornady flat base seated at an oal of 2.700".   That load over 26g of H335 is the best I've found so far, but it is loud.

Have fun.  Working up a good load combo is almost as much fun as shooting one.

Nate C

[Old Syko]

Nate, you rite about that 139gr. Hornady.  Thas my favorite bullet in the 7TCU.  Only thing is i shoot it over 26.5gr. of H322 and a CCI400 primer at an OAL of 2.625.  In my present 14" factory barrel them little bitty bullets leave a thing that resembles a shotgun pattern.

Natty, dem Dramboobies is OK but this Makers Mark never goes bad!

[Robert]

I could not beleive how accurate they are. Better than jacketed Sierra 100's. I am not trying to advertise, but these bullets will make you laugh, especailly for the price.  The TCU for some rerason, really likes these bullets.  Ask PJ.  He'll back me up.

[# 566]

IF you really want a case with the MAX length, use the 222 Rem mag, case. take a .222 RM case and chamber it, the longer case should require a little force to close, this will form the head space , next load some 231 or other fast pistol powder, go to the range, load and position the powder by raiseing the muzzle, then fire as you normally would, you will see the case has filled out to the end of the chamber and will show you the max length of you hamber, Now trim, ect.
I compaired .222 RM cases VS .223 cases and couldn't see any difference, other than I couldn't use he .222 RM cases in a match when I was fire forming cases