Author Topic: Poor accuracy from 125gr TC  (Read 618 times)

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Offline Black Jaque Janaviac

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Poor accuracy from 125gr TC
« on: June 18, 2003, 06:14:56 AM »
I've got a Lee .356" mold that casts 125 grain Truncated Cones.  I got it originally for 9mm but since the as-cast diameter is .358" I tried it in my .357 Rossi rifle.  

At 25 yard I've punched cloverleafs with 5-shots.  But at 40 yards it opens up to around 2".  Is the TC design just tough to get any accuracy with at farther distances?

I shoot a 158 grain RNFP and that has produced some wonderful groups at 40 yards.  The 158 grain bullet also happily rings a 16" gong at 200 yards too.  

I like the idea of having a lighter bullet to cast.  Sometimes all I ask of the bullet is to dust a piece of charcoal.  I don't need 158 grains of lead to do that.

I was wondering if anybody has tried Lees new 125 grain RNFP in a .357.  Has accuracy been good?
Black Jaque Janaviac - Dat's who!

Hawken - the gun that made the west wild!

Offline triggermortis

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Poor accuracy from 125gr TC
« Reply #1 on: June 18, 2003, 06:53:10 AM »
B. J. J.,

   I recently got a Lee SWFP double mould that is designed to be a 150 grain caster.  What I've cast with straight wheel weights have been a consistent 146 grains, and all my guns shoot them well 'as cast' with a coating of alox.  I also water quench.

   My Rossi 92 won't feed 38's right, so I load these bullets in magnum cases, and it shoots very well.  

T. Mortis (81 weeks to go)
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Offline John Traveler

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.358" TC bullets
« Reply #2 on: June 18, 2003, 07:06:21 AM »
Black jack,

I too have had only so-so accuracy from 9mm and .358" truncated cone bullets (Lyman and Lee molds).  The profile copies that of the FMJ TC military bullets.

The problem seems to be common, as several of my shooting friends and aquaintances have also described it.

Part of the problem with the Lyman bullets is that sizing to .356 frequently makes for an unsymmetrical bullet as seen on the bearing surface.  I use those only for plinking.

We have come to the conclusion that the TC design gives only modest bearing surface and no bore-riding support from the nose profile.  None of us have any accuracy complaints from similar-weight Lyman and Lee 125g RN cast slugs.
John Traveler

Offline Leftoverdj

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Poor accuracy from 125gr TC
« Reply #3 on: June 18, 2003, 07:43:14 AM »
I have a 135 grain TC mould that works very well in .38 pistols to 50 yards and stays at about an inch at 35 yards in a rifle. Forget whether I got that mould from P&C or NEI. The nose is much shorter than the Lyman 125 TC I usta have.
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Offline Black Jaque Janaviac

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Poor accuracy from 125gr TC
« Reply #4 on: June 19, 2003, 03:37:22 AM »
Nose length - yes I was wondering about that.  

When I look at the profile, it looks like the cone part is as long as the straight part (I forget what you call that).  It just looks like it won't travel far with any great accuracy.
Black Jaque Janaviac - Dat's who!

Hawken - the gun that made the west wild!