17 Hornady Hornet factory load measurement

[drewh]

Larry,
It is on a cone breech Bat SV, and set up to head space on the shoulder.


Drew

[trotterlg]

Well I would say that is the problem. If you don't have a SAAMI chamber you really can't expect all factory loads to chamber properly. In effect you have a wildcat with only your (and some other factory) rounds fitting like you want. I would have him cut the chamber to fit the longest factory rounds you can find, let the others headspace on the rim so they will grow to match the long ones. Larry

[bburrell]

I am still having a hard time understanding your issue. Case length should be the same on any new loaded brass. Is your concern with the headspace on the case or is it the oal to the ogive of the bullet? Depending on how much throat you gun smith created before starting the lands, you may very well need to seat some bullets deeper than others if there is very little throat. Do you have an OAL guage so that you can measure distance to the lands with each bullet type?
Burt

[trotterlg]

I think what he was trying to do is use a .22 comparator to get a measurement to the shoulder of a 17 Hornet case. Seems he had a chamber cut to headspace on the shoulder and now some other brass will not chamber properly. Not a big surprise to me, the case is intended to seat on the rim, so to headspace on the shoulder you need to only use your sized brass to get it right. Larry

[drewh]

As painful as it is, Larry is 100% correct on this, for this reason; Hornady sent me an ANSI drawing for the cartridge and their length tolerance is +.015. So by their definitions both lots of ammo are within their tolerance specs, the gunsmith's are close to minimum spec and mine are towards the upper end. The 2 conclusions I can draw from this - 1 I will not be able to use factory ammo reliably, but will be perfectly fine loading my own, where I can control the shoulder length, 2 this leads me to believe that the factory chambers for this cartridge will all run longer than minimum spec by somewhere around the maximum tolerance to accommodate all the ammunition variation.

Drew

[Daryl]

# 3/. - headspacing on the rim as with headspacing on a belted case, allows gun manufacturers to be VERY sloppy with body lengths, something they cannot do with rimless ctgs.