The .22 Hornet is often called an inaccurate cartridge. It is - and it isn't. The difference is in how it's loaded.
The hornet has very little case volume, and the case neck brass is so thin that reloaded rounds have little neck tension. The two factors combine to cause great inconsistencies at ignition. First, some primers may be powerful enough to actually unseat the bullet and jam it into the rifling before the powder fully ignites. The resultant "double shuffle" of the bullet first causes the case volume to increase, then stop changing, and then increase again as the bullet finally engraves and moves on down the bore.
All that happens as the powder is lighting, and the abrupt changes in case volume mean that no two charges ever ignite the same, build pressure on the same curve, or burn out at the same time.
Likewise, the bullet never obturates the same, never engages the leade the same and never engraves the same. None of these results are conducive to accuracy or consistent velocity.
So how can it be fixed?
First, a mild primer in this or any other small-capacity case will cause the least disturbance of the rifle, won't dislodge the bullet and has all the ignition energy needed for such small charges of powder. The hornet is also a relatively low pressure round and a thick hard primer cup isn't needed for safe pressure containment.
I recommend and use the Rem 6 1/2 small rifle (very mild), or the CCI 500 or Fed 100 small pistol primer. Avoid Winchester primers, rifle or pistol, any magnum primer and the Rem 7 1/2, all of which are way too hot for the Hornet.
I favor a case full of LilGun as propellent because it is a low-pressure powder in this use. Next best is AA1680, followed in distant third place by W296/H110. LilGun is better with 40 and 45 grain bullets. If you absolutely must try a lighter bullet like the Calhoon 37-gr Double Hollowpoint, then W296/H110 works very well indeed.
Finally, the best results will come if you use the Lee Factory Crimp Die. Remember those super-thin case walls? You really must crimp to make sure the bullet doesn't do that double-shuffle, and the Lee FCD can be used even with bullets that don't have a cannelure.
Try all three remedies together (mild primer, LilGununder a 45-gr bullet, AND the Lee FCD) and your Hornet will shoot like a different gun. Honest.
I was skeptical of RockyRaab's advice above so I had to give it a try for myself:
Friday, November 10, 2006
Well made it to the range today (took a vacation day) and tried some new loads for my Browning Micro Hunter. Slight breeze today, but steady. Results are one five shot group at 108 yds for each load.
Thanks to all who recommended LIL'GUN and the pistol primer preference. I found my 296 load prefers a rifle primer but LIL'GUN likes the pistol primers best.
13.0 LIL'GUN with a Hornady 40 gr Vmax bullet
Rem 7/1/2 Rifle Primer 1.57"
WW Pistol Primer 0.97"
Rem 1 1/2 Pistol Primer 0.80"
11.0 296 with a Hornady 40 gr Vmax bullet
Rem 7 1/2 Rifle Primer 0.85"
The LIL'GUN loads are 2950-3000 fps (primer dependant) and the 296 load is 2800 fps.
