strange(?) bullet performance question

[jayd4wg]

hit the range today with 2 boxes of 22WMR for my Marlin882ssv, and noticed a very strange anomoly.

I'm zero'd with Hornady 30gr VMAX bullets that normally cook right along at 2270-2300 fps

I did not want to blow thru my hunting ammo to plink with, so i bought a box of cheap 40gr CCI HP's and USUALLY, this would simply move my POI from 1" high at 50 yards to dead at 50. today however, elevation did not change, but the CCI landed right 1.5" and maintained excellent grouping. NEARLY as good as the hornady stuff which has been shown here to produce fantastic groups in my rifle.

why would a slower load maintain the same vertical POI as a faster one with no change to scope or platform?

The ONLY mod that has been done to my rifle since the last time I shot the CCI stuff was adding some sand and epoxy to the butt to add some weight to the rear of the rifle changing its balance a little...

I am a tad bit stumped here...

 

[Hellbender]

Re: strange(?) bullet performance question

Harmonics.

Many times a slower load will hit higher (at shorter ranges) on target than a faster load. Or right or left.

A barrel does not whip only up or down, but in a weird reverse spiral whip (if free floated).

So it all depends on where the bullet exits during this spiral whip.

Also, during the recoil cycle, a faster load will exit the barrel sooner and normally hit lower. Seems counter intuitive, but think about it. This really shows up when shooting very light guns and handguns. Also adding weight to the gun will exaggerate this tendency.

 

[vman]

Re: strange(?) bullet performance question

How is the performance further out? Do the 40grains drop lower than 30gr vmax when you take them out to 100?

 

[TOP PREDATOR]

Re: strange(?) bullet performance question

i'm using the same rifle and the same 30 gr horndy, and cci 40 gr FMJ for turkey.

shot through a crony and depending on weight sort, average of 5 rounds:

30 gr. hornady, 2200 is the advertised speed
55.0 + 55.1 GR = 2151 FPS 3 highest of 5 shots averaged 2198 FPS
55.2 + 55.3 GR = 2171 FPS 3 highest of 5 shots averaged 2207 FPS

cci 40 gr fmj
62.8 + 62.9 GR = 1877 FPS
63.0 + 63.1 GR = 1936 FPS
the 6 highest out of the 10 averaged at the 1910 FPS advertised speed

when switching from the hornady to the cci, to get a zero at 50 yards, according to my notes i have to go:

7 CL DOWN AND 7 CL RIGHT = 0 AT 50 WITH 40 FMJ
so with my 1/4" @ 100 adjustment scope, that means the 40 gr fmj is hitting a little over .75" high and a little over .75" left at 50 yards as compared to the hornady.

although i have tried the cci 40 gr hollowpoints, i didn't keep any data on them as i prefer the better penetration of the fmj for turkey.

i did keep data on the cci 40 gr gamepoints (lead spire point):
63.9 + 64.0 GR = 1804 FPS 3 highest of 5 shots averaged 1798
64.1 + 64.2 GR = 1829 FPS 3 highest of 5 shots averaged 1812
64.3 + 64.4 GR = 1790 FPS 3 highest of 5 shots averaged 1802

when adjusting from 30 gr hornady to these i have to go:
10CL DOWN AND 10 CL RIGHT = 0 AT 50 WITH 40 GR G.P.
or 1.25" high and 1.25" left compared to the hornady

so same manufacturer (cci) and bullet weight (40gr), even a slower average speed across all the weight sorted ammo compared to the 40gr fmj, and it's hitting higher than the 40gr fmj.

so what HELLBENDER is saying above may explain it with the harmonics and the weight added.

with a 50 yard zero for each ammo, at 100 yards i get a drop of:
hornady 30gr vamax -1.25"
cci 40 gr fmj -2"
cci 40 gr gamepoint -2.25"

with the hornady grouping much better than the other two.

 

[jayd4wg]

Re: strange(?) bullet performance question

i'll blame harmonics...it's the only thing that makes sense. Last nite i went thru the rifle and cleaned things up and checked the stock out for binds with modelling clay. the action is making same contact points at all locations it previously was with little or no change. Just the added weight. luckily the weight is in a plastic baggie that was forced into the hollow stock and I can remove it. I'll do so and try again to see if it changes or if i just have a different lot of ammo from CCI. My bet is on the ammo lot.

I will also check further down range performance. I'd really like to use the 30gr bullets on the turkeys this year. I'm confident i can hit the base of the neck and it will definitely incapacitate the bird...but the 40 grainers tend to hold together better. I'd really like it if the winchester 40 grain bullets (soft points) would group worth a snot. they are FINE fodder for fox and yote, and surely would take the fight out of a turkey to boot.

TP, your data is pretty close to mine. One thing I did find is that my rifle will shoot the 40gr CCI HP's and FMJ to the same POI.

I'm toying with the idea of taking a few inches off the barrel to cut down on some weight...up there. that was the whole reason I added weight was to change the balance of the rifle. The other part of me says quitcherbitchin and live with it. The rifle shoots good...its the nut behind the butt that is "uncomfortable and whiney"...

on the subject of more penetration for turkey...where do you hit them TP? I've been taught to punch them at the base of the neck...its the one part of their body that moves less than their head yet offers the largest single target for instant death when hit. I'd imagine with FMJ you are going for wing socket or hips? In looking at how the 30 and 33 gr vmax bullets perform with a total explosion at 4" penetration in gel, the base of the neck should be LIGHTS OUT for the old birds...no?

I have yet to punch a turkey. Got the fingers crossed for this fall. Been seeing ALOT of birds and hoping the early autumn we are going to have will make it a little easier to spot them coming at a distance when calling.

 

[TOP PREDATOR]

Re: strange(?) bullet performance question

the 40 gr fmj to the wing socket will do it without busting up a ton of meat with a hollowpoint or polymere tipped. plus if your a little off on the wing socket, it'll take out the spine or the vitals. a higher percentage hit than the base of the neck.

i liked the way the 34 gr. winchesters grouped, but a bit explosive on just about everything, not enough penetration for turkeys. my buddy had many get up and walk away using those. i did smack him in the head for not changing the ammo, he uses the fmj now.

then the hornady ammo came along and (at least in my rifle) blow the others away - very accurate but super explosive on stuff, that's why i went to the fmj for turkey. after the season it's back to the hornady.

i was expecting more out of the gamepoints, they didn't group at 100 as well as i expected, i figured they would be the best for turkey / coyote as they are built to act like a centerfire lead point with mushroom effect. but the open groups turned me off.

i did the base of the neck thing with a .223 55 gr fmj at 140 yards, the bird just dropped, but that was with a .223 and not a .22 mag.

would love to see hornady put out a fmj.

sorry to go off topic.

 

[jayd4wg]

Re: strange(?) bullet performance question

man...i'm just full of typos up there. meant to say "i'd really like to try the 30gr's on turkey this year" and have fixed the others...

 

[frog5215]

Re: strange(?) bullet performance question

Hell, you can throw a rock through 'em.
.22LR solid SV in the upper body/wing butt area works fine; My kids have killed a mess of 'em with a Martini WMR and various 40gr softpoints, though solids ought to work fine.
I like 46gr Hornet factory loads (Rem). I think my 700 .221 Fireball is a little hot, I guess I could download to light Horner levels.