Okay, back from the range, muddy boots and all... [img]/ubbthreads/images/graemlins/frown.gif[/img] [img]/ubbthreads/images/graemlins/laugh.gif[/img]
Folks, I can't tell any difference. That doesn't mean that there isn't some
difference--just that with the handloads and factory loads I was shooting, the ES would appear to eclipse any actual difference in free recoil velocity versus firmly held velocity.
Now. There's an additional surprise which we can chew up another gross of pencils over which I'll save for the end of this post... [img]/ubbthreads/images/graemlins/smile.gif[/img]
I first shot a little Model 34 Smith & Wesson .22LR (revolver), with a 4" barrel. Checked six shots (CCI Stingers), three with firm hold, three with as loose a hold as I could manage and still pull the trigger.
FH = Firm Hold, and FR = Free Recoil:
Then I shot a 1911A1 45 ACP, using 230 grain surplus ball ammo. For the FR shots, I just put the butt of the pistol on a sandbag and used my thumb to compress the grip safety and my index finger to squeeze the trigger (yeah, don't try this at home!)... ES's were bad, but here are the averages of ten shots firm, ten loose...
For the record, one shot of the FH went 801 fps, and one shot of the FR dropped to 693. These two numbers pulled the averages pretty close. If I count those two odd shots out, it looks like:
On to the rifles. These were shot off a bench, and for free recoil I just used my thumb behind the trigger guard and my index finger pulled the trigger.
On my pre64 Model 70 Winchester in .270 win. Load was 60.0 grains of Accurate Magpro with Sierra 150 grain Gameking:
6.5 x 55 Swedish Mauser, M38 Oberndorf. Load was 46.3 grains RL22 and Sierra 142 grain Matchking.
Please consider that this info is probably worth about what I charged you for it. But from what I saw today, when I was actually trying to figure out the effect of loose or firm hold on velocity
, I have to recant my previous assertion that velocity can change all that much based on how firmly the gun is held. In fact, the crude little test I did today would seem to indicate that free recoil increases
velocity as often as it decreases it--but I'm sure that's just a fluke...
I would still like to see some numbers from some other members who may take time to try this little experiment out next time they go to the range. There may be particular scenarios (certain gun, certain cartridge) where there is a more noticeable difference. I'm not at all familiar with the double rifles Bart mentions, so I can't really offer anything there...
Okay. For the surprise I mentioned earlier...
Why doesn't the POI on target change noticeably between FH and FR? It's supposed
to. Everybody always says it will. [img]/ubbthreads/images/graemlins/confused.gif[/img] Granted, none of the rifles I tested today were shooting BR sized groups, but both were printing about 1.5 MOA with the loads I brought along. Holding at the same bullseye during free recoil seems to land the shots right in the group--even though the rifles were thrusting backward a good three feet (into my cousin's hands, who was standing behind the bench to catch the rifles during FR firing). I would have thought that POI would have been significantly
different with FH versus FR. I would have to assume that with bug-holing BR rifles, the POI shift is more noticeable at 100 yards... But I'm glad no one asked me how that would have turned out before I did my little test today.
I would have been wrong twice! [img]/ubbthreads/images/graemlins/blush.gif[/img] [img]/ubbthreads/images/graemlins/laugh.gif[/img]
In any event, it appears that I was wrong once, so here I go...