Weird 22 Hornet Groups !

[Mirage]

Can anyone shed light on this?

Have a CZ 527 22 hornet. Just started working up loads for it, results are great but perplexing!  

RP case, wsp primer, neck sized with Lee collet, seated w/ Forster BR. Hornady 35 gr vmax .035 to lands. Following groups represent average of (3) ~ 3 shot groups.

1 minute between shots, 5 minutes between 3 shot strings. Clean bore and wait 10 minutes betwen loads. BBL. is cool and clean for each powder.

W296 11.8 gr: 15/32" group, 2.5" high, 1" right.
H4227 11.3 gr; 12/32" group, 1.5 high, 1" right.
Lil' Gun 13.0 gr: 19/32" group  0" high, dead center

load data pegs Lil gun @ app. 2842 fps, W296 @ 2950 fps, h4227 @ 2800 fps


Why does LIL Gun consistently group lower and to the left of the other powders?  I have reversed shooting conditions to rule out temperature, wind etc. in repeated range trials (shoot w296 first, cool temp, no wind etc) and obtained same results.

Similar results with Hornady 45 gr. hornet bullet (overall prints lower)

What gives with Lil Gun relative to others ??

[Double D]

Simple, three different powders that have three different burn rates generating three different pressures at three different burn temparatures and three different barrel dwell times.

Book predicted velocities are only that predictions. Actual chronographing will tell the tales.

Here's my WAG. The Lil Gun is generating higher velocities and higher pressure and decreasing bbl dwell time.  The bullet is out of the bbl faster so the effect of recoil doesn't get transmitted to the bullets path as quickly as it  does with the others.  I suspect that is the case based on my own experiance with the Lil Gun

Of course the other side says that velocity with Lil Gun is down and the effects of recoil are less.  That is supported by the book predicted velocities.  

I can tell you from my experiance that Lil Gun gives very some very different results from gun to gun.  12.3 grs. blew primers in the Martini Cadet and worked fine in the TC.  

All those groups you are getting are awesome.  You need to get a chronograph and run them across.  Find out which load  has the smallest extreme spread and standard deviation and that 's your load!

Don't consider where a group prints on a target in relationship to other groups, it's irrelevant.  Once you find the load you like, that's what the knobs are for on the scope!

[Mirage]

Interesting theories. I should chrono the loads (so many ways to spend money ! when reloading !).  As an alternative to chrono, what about this.

1. shoot and measure group (elevation) at 100 yards.
2. leaving zero unchanged, shoot and measure elevation at 50 yrds.
3. run different initial velocities through ballistics calculator (point blank
    etc.) until you get a match on the 50 / 100 yd elevtions.

do you think this is an acceptable way to "rough in" velocity. Obviously errors will exist in measuring group, shooting ability etc. as opposed to chrony.

Mirage

P.S.

Double D, I lived in Missoula for a while (attended U.M.). Montana is awesome, if I could figure out how to earn a living in MT I would leave in a heart beat !

[Double D]

Don't forget to factor in barometric presssure temperature and altitude.  Factoring in 50 yards isn't helpful  you won't be able catch the minute difference .  It's better to go the other way 100 200 300.

I tired this with my 338/308  a couple of years ago when I was still in Montana. I bought an Oehler Chronograph and found my estimates were as much as 400 fps off.   3800 ft elevation vs sealevel

Please forgive any typos in this post, the glasses are up stairs.

[Iowegan]

I agree with Double D. The point of impact will vary with different loads. Vertical stringing is almost always from different velocities.  Horizontal stringing is releted to different powder burn rates or peak chamber pressure that influence the barrel's harmonics. The barrel is like a tuning fork. The shock of the peak pressure makes the barrel vibrate. Honestly, you really don't care much about harmonics. Looks to me like your H4227 shot the best. I would load more of those and readjust the scope.

As for computing velocity from point of impact at different distances: It's like shooting in the dark. Buy or borrow a chronograph and see what the loads are really doing. As mentioned before, the velocities stated in reloading manuals are rarely what you will actually measure from your gun. There are just to many variables when you try to compute velocity.

[Duffy]

If it makes any difference, my 22K Hornet in the Encore is sort of finicky with different powders and even primers. I understand with this cartrige once you find a load it's best to just stick with it.

Ryan