Starting Conicals

[Dan Chamberlain]

How easy or how difficult should it be to start a conical at the muzzle.  Is being able to finger start the conical an indicator that the bullet is too small?  The lands scribe the driving bands, but the bullet doesn't fill the grooves.  I expect that the bullet is supposed to obturate and buck up to fill the bore.  My recollection from about 30 years ago was that the Thompson Maxi Ball was pretty easy to start as well.

Dan

[roundball]

Yes, they are what's called a "slip-fit" design...I've used TC Maxi-Hunters and Hornady Great PLains conicals, (bother extremely accurate in my .45cal x 1:48" barrels) and they all start just like that.

It's actually beneficial in that with a little care you can easily ensure that you get them "slipped" in good and straight so they're properly aligned with the center-line of the bore when you punch them through the rifling with a short starter.

Caution against trying to seat them by short-shafting a ramrod as there's often a certain about of wallowing around before the conical driving band finally gets cut through and that usually leaves less than optimal cuts through the driving band...a short starter will punch them through cleanly & sharply so they have as snug of a fit on the lands as possible.

[Dan Chamberlain]

The reason I ask, is that I just received a barrel from Bobby Hoyt that he's relined for .458 in a Lyman Great Plains barrel I sent him.  The "as cast" bullets I have for this barrel at 345 grains and they start pretty easily, only showing a lot of resistance at the last driving band toward the nose of the  bullet. 
There is contact at all the driving bands, but the last one shows the most resistance. 

I'm hoping to approximate the .45-70 in my GPR.  Don't want to go any higher than 75 or 80 grains so with this bullet and that load, I don't expect to get a breech plug through my forehead. 

Dan

[roundball]

There is contact at all the driving bands, but the last one shows the most resistance. 

And that's normal...that last band is the "driving band"...basically gets the biggest bite from the lands as it's the band which is the primary driver from the rifling...hence the name "Driving Band"

[Dan Chamberlain]

Thanks.  Can't wait to test this beast.  The crescent butt plate will be fun!  I had a similar butt plate on an "86" Winny in .45-70 and with mild loads it wasn't too bad...!  Thankfully I have the discipline to stay inside my 75/80 grain limits.  I have other behemoths to use if I feel froggy.

Dan