Lee 120 gr TC Mold data?

[milprileb]

Seating depth for the Lee 9mm 120 gr TC mold bullets has me a bit stumped.

The Lyman manual has a near brother of this bullet and show OAL to be 1.110
and that leaves lube band a bit exposed when seated in 9mm brass.

Does anyone have a Lee manual and would tell me what they recommend for a OAL for this bullet.

Right now I seated the bullet till the lube band is beneath the case mouth.

My pistol will take the 1.110 OAL round. I made a dummy and it feeds and cycles slick
but the edge of bullet lube band peeks from case mouth and I am not going to use this OAL.

Thank you very much

[Echo]

I would seat the boolit so that the lube groove is inside the case, and check for reliability of feeding, and accuracy.

[EMC45]

I load that very same Lee bullet and I load it so there is about .030 of the front driving band showing above the case mouth. Feed and function (accurate) just fine in my BHP. BTW the Lee manual is thick and extensive, but they don't offer data for their cast bullets in it. I like it though. It is a good manual and has a bunch of info.

[CPL Lou]

I seat mine at 1.066" LOA.
Works fine in my SIG P225 that way.
My load is 4.8 grains of Unique, winchester cases, cci 500 primers.
I size my bullets to .358" even though my barrel mic'd out at .355".
I tried .356" and .357", but got some leading, with my alloy, until I tried .358".

Good luck !

[fecmech]

Loading that boolit at 1.058" will give you the same amount of bullet in the case as the Lyman at 1.110. Both bullets weigh the same and have the same bearing area. The lyman just has a longer slimmer nose. I used all the Lyman data with the Lee bullet at 1.065 in 3 different guns and never had a pressure problem with max loads.

[milprileb]

Thank you Gentlemen !

[b2948kevin]

Great topic. I had this same question and just found my answer.

[OEF2012]

I know this is an old thread, but I wanted to say thank you for the info

[MtGun44]

Here is another way to look at setting seating depth - from a feeding standpoint.

http://castboolits.gunloads.com/attachment.php?attachmentid=52652&d=1314925371

Note the 9mm ball round behind the 120 TC round. Setting the front corner
of the boolit so it falls on the curve of the ball round's nose will ensure similar
feeding geometry.

Bill

[JeffG]

I set mine to 1.07 with that bullet, for use in S&W SD9VE, sized .357 The TL version of the TC round I set to 1.145. I set the non TL round at that length just to keep the lube groove inside the case for better support.

[lead-1]

Another vote for the 1.06" area, my Kel-Tec has a liking for this boolit seated deeper than my other nines thus the 1.06" COL.

[tazman]

My 9mm pistol is a poor choice for recommending a specific COL. It has generous chambers and a long tapered throat which will feed and shoot almost anything you can fit in the magazine.
I guess I got lucky with this one.

[Blackwater]

The best way to seat a bullet you're not familiar with on the first try is to take a RN factory round (jacketed or cast doesn't matter - you're only interested in profile, and material doesn't matter there) and adjust your seater so it just fits that round. Then try it. If there are problems feeding, usually you'll want to seat it shorter, but if that doesn't work, try just a smidge longer. Sometimes it just takes a little experimenting to see what your gun wants to feed most reliably. If you only get a bobble or jam now and then, the distance you need to adjust your seater should be minor, but minor differences CAN make a BIG difference. You've just got to try them to see. Different guns, sometimes of the same make and model, will need slightly different OAL's to get the same good results. There's no way to short-cut this, either. You've just got to PROVE your OWN gun with each bullet. Sometimes we WANT simple answers to questions that don't lend themselves to cut-and-dried answers, and this is one of those questions that always has to be answered with a "it depends," because every gun is a law unto its own self. Good excuse to do a little more shooting, though, and as an added benefit, sometimes it can add accuracy as well - not always, but sometimes.

[MtGun44]

Mine is seated to 1.075" and works in numerous 9mms just fine.

Make sure you are taper crimping as a separate operation and the
case mouth is slightly smaller than just a bit closer to the head end.
Basically, I do not subscribe to the "just remove the flare" method of
taper crimping - this has given me a few failures to close on various guns
over the years, so I always want a bit of actual taper in the taper crimp,
not just removing the flare.


Bill

[zomby woof]

My Witness steel has a very long throat. I load that boolit to 1.140. I use coated boolits so the lube groove being exposed is no big deal.

[Cherokee]

I have loaded and shot over 20k of the Lee 120 TC lube groove CB in various 9's. All were seated at 1.055" and have been 100% reliable. Also great CB for 38 Super.

[Case Stuffer]

My Lee 356 120 TC 9 cavity arrived yesterday , I cast a few hundred ,powder coated them ,sized to 0.357 loaded five seated to 1.070 overall over 5.9 gr. of HS-6, fired these to check functioning which was fine. Next up is more rounds to prove reliability and to check accuracy or at least to confirm these do not tumble,keyhole and such like the Lee 124gr. TC TL ones do in my SA XD-9 SC.