Watch out for Hornady 40 dies...

[munitor]

Put a new set of Hornady TiN dies to work the other day loading 40 S&W for IPSC. Lo and behold, all rounds failed the bullet setback test. All rounds were loaded to SAAMI spec (0.420 crimp at the mouth, 1.135 OAL) like I always do, and I used R-P brass and bullets from a lot that I know are ok because they worked fine when I did a batch of 500 through my Dillon SDB. I tighted the crimp, but nothing I did would keep the bullet in place when pushed on.

I measured the case diameter just under the base of the bullet and found that the loads out of the SDB measured 0.418, while those from the Hornady dies were measuring 0.421. Intrigued (and scared), I ordered an RCBS, Dillon and Lee sizing die to see if they were the same. Dillon came in at 0.418, RCBS and Lee at 0.419. All these passed the bullet setback test.

I called Hornady to find out about this 40 die and the first thing they asked was if I was using RP brass. When I said yes, they said they had recently opened up their sizer because people using Federal and Winchester brass were complaining that it was working the brass too much. Not long after that, complaints started coming in about RP brass. I asked if they had tightened the spec on the sizer back down and they said no.

Folks, this is a dangerous situation. I recommend you not use Hornady 40 dies with RP brass unless you have checked it for bullet setback resistance. In fact I always test all 40 S&W rounds, and this is a good example why.

[BigDave]

can you elaborate on the 'bullet setback test'???  I just getting started using a 650 to load 40 w/ Dillon dies.  I don' t want ignorance to bight me in the backside.

[Flexmoney]

Dave,

I'll give ya a quick a dirty version.  Someone with more extensive knowledge can take it from there.

If the brass isn't holding the bullet tightly enough the bullet can get pressed back deeper into the case (reducing OAL).  This would result in highier pressure...might be enough to blow up the gun.

The bullet can set-back through handling or, most likely, when the round is stripped on the mag and the bullet hits the feed ramp.

I think Matt Burkett has written about a down and dirty way of checking.  he takes a loaded roung and presses it between his bench and thumb, measuring OAL before and after.

[benos]

" he takes a loaded roung and presses it between his bench and thumb, measuring OAL before and after."

That's pretty much it, except most use a round instead of a roung.

be

[Flexmoney]

...which brings up another point.  Where is the spell checker button on this board???