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I am just wondering on the 7mm TCU if anyone loading it for Contenders uses a max OAL longer than 2.6"? Getting ready to load for a new 14" barrel but wondering because I am making a 3d printed ammo carrier, I was backing the boolit 10 mils or so off the lands on the 10" barrel but someone else may have a longer leade?
Should be fun :)
Depends on the specific bullet and who made (chambered) the barrel.
As an aside, did you chamber cast the barrel? T/C varies in the freebore AND Leade among barrels. I often wondered if they had 20 or so chamber reamers lying around. :-)
What he said. Every one I've seen was different. And of course it depends on what bullet you want to use as well.
With single shots, I only measure OAL for repeatability. Some bullets like to be nearer the "throat" of a contender barrel, some don't. A throater could do wonders to some of the areas between the neck and the rifling in some of these barrels, but I have yet to own or shoot one that isn't pleasantly accurate.
I have competed with Contenders for years (over 35) in Sillywett. I can say with some degree of certainty that the throats vary to some degree or another and have used the barrel itself to determine the OAL. I take a once fired case and put a light crimp in the mouth to hold a sized bullet (barely). Chamber the round and upon removal I measure the OAL then back off .010" and load accordingly.
Haven't dug the barrel out yet, good thoughts!
Depends on how many rounds thru it too. Friend shot silhouette with a 7tcu and I would swear there wasn't any rifling for the first inch ahead of the chamber, it had been shot so much. He finally sent it back to TC and they sent him a new one.
On dads 14" I can seat a 140gr sp out so far there is only .1" inside the case. Very long throat but shoots great.
I haven't loaded many but all of mine so far have been seated to 2.551 and I have had pretty good results. I am not an expert (Still learning)
So long as the storage case has a long enough OAL it'll be fine, if the allowed length is 50 mils longer than I ever load that's ok :)
The couple I have played with (Super 14 and 21") had extremely long throats, long enough that I had a difficult time getting 175's to hit the lands...both were still fairly accurate, though.
My 10" barrel you couldn't get very near to the lands with a 120 grain bullet and still have over 1/16" seating depth in the case, I mostly shot 160 gr projectiles in it though.
For my 10" S/S 7TCU barrel with an RCBS 145 Sil bullet my overall length is 2.465". I have an XP100 7TCU that needs 2.580" with the same bullet. I size the nose on both of those to .277" and the nose slides into the rifling, just barely leaving rifling marks on the nose section of the bullet.
The 145 RCBS is a bore rider, designed for the nose to just touch the lands. Shot them for years with 15g H-4227 under spherical buffer, in moving steel competition. Including my shoot off load. My OAL setting was .003 off the lands in my 7TCU guns, 10”, 14” TCs and XPs, all had different OALs. But using the Speer 140-145 to setup then loading the 130s and 160s to that OAL die setting with 748 works well for jacketed bullets. Been a long time since I loaded a jacketed bullet in the TCU.
Not to HIJack the thread, but, even with the great popularity and Very top shooting of the 7 TCU in Silhouette after it came out-mainly with jacketed bullets being used, I went another direction:
I started with the 357 Herrett in 10 and 14"/200 gr cast bullets. Good knock down, but heavy recoil, esp in the 10". (This was back in the days of Full Set Rams.)
Then I procrastinated about the 7TCU when it was introduced.
But, because I was already an inveterate cast bullet shooter, I went with a 10" 30-30 for Production. Nothing but cast bullets.
I figured the heavier bullets would produce more Momentum at the ram line than the usual lighter 7mms.
My load of a 311466 bullet, HT at 160grains weight clocking 1900 fps over the Oehler 33 was a great shooter. NEVER lost a Ram.
I won the Saeco High Cast Bullet belt buckle in Production at the '82 Internationals with the 30-30
and also , in another local shoot off after a tie at 39, hit 7 of 10 beer cans at 200yds to win it.
beltfed/arnie
My Apologies for HiJacking the thread and diverting to 30-30 Contenders
beltfed/arnie