Weird results from 45 ACP test loads...

[crimsondave]

OK, I found my ball ammo load for my 1911 yesterday. 4.0 gr of Bullseye.

However, in the process, I found, except for my 4.2 gr of Bullseye test load, all my loads above 4.0 gr hit lower at 25 yds than my 4.0 load. I went all the way up to 5.3 grs. Thought that was weird.

[Unclenick]

Your 4 grain load (5 grains is the old military load) is so slow getting out of the barrel that the slide is just starting to push the barrel to unlock before the bullet clears the muzzle. That is what is tipping the muzzle up.

You might consider a stiffer recoil spring, a lighter bullet, or, better still, the square bottom firing pin retainer (Browning's original design), which cocks the hammer from a contact point lower down on it. That lowers the slide's mechanical advantage and slows the unlocking. Muzzle flip and perception of recoil are both reduced by that change, as well. The only cost, same as a stiffer recoil spring, is the slide feels a bit stiffer to rack. It doesn't bother me, though it is the reason the military added the radius at the bottom of the firing pin stop: easier slide operation.

[Jector]

Sorry, don't mean to hi-jack the thread but, unclenick, your reply inspired a question. Do you know of a place on line that will explain how a 1911 works? I don't understand your reply. Thanks.

[LHB1]

Dave,
Nope. That's normal. Faster pistol loads get out of the barrel quicker (before recoil has lifted the barrel as much) and therefore hit lower on target at close ranges.

[Slamfire]

Heck, I don't know. I have had funny things happen to elevation when increasing loads.

And sometimes not.

If the load is accurate, functions well, and you plan to use it a lot, get higher/lower rear sights. Kimber sent me a rear to correct an issue I had with elevation, and life is good.

I tested a bunch of different loads with Bullseye and the 230 LRN bullet. I settled on a load of 4.5 grains. I want my 230 grain loads to just at 800 fps, but I will also say, I have shot many ammo cans worth of 230 grain ammo that just clocked at 700 fps. The stuff shot well and was easy on the wrist.



Kimber Custom Classic M1911

230 LFN Bull-X 3.5 grs Bullseye Mixed Brass WLP OAL 1.20" taper crimp .469"


8-Jan-06 T = 61 °F

Ave Vel = 643.6
Std Dev = 14.07
ES = 63.63
High = 679.9
Low = 616.3
N = 32

shot a little high Pistol cycled each shot



230 LFN Bull-X 4.0 grs Bullseye Mixed Brass WLP OAL 1.20" taper crimp .469"

8-Jan-06 T = 61 °F

Ave Vel = 715.9
Std Dev = 11.45
ES = 48.32
High = 742.9
Low = 694.8
N = 32
shot a little low





230 gr Valiant LRN 4.0 grs Bullseye Mixed Brass WLP OAL 1.250" taper crimp .469"

29-Jan-06 T = 68 °F
Ave Vel =698.8
Std Dev =10.19
ES =36.33
High = 713.5
Low =677.1
N =28

V. Accurate


230 gr LRN Valiant 4.5 grs Bullseye lot BE532 (80's mfgr) Mixed Brass WLP (brass) OAL 1.250" taper crimp .469"
16-May-09 high 83 °F

Ave Vel = 782.7
Std Dev = 13.41
ES = 52.05
High = 815.5
Low = 763.4
N = 28


230 gr LRN Valiant 4.5 grs Bullseye 99' & 2005 mixed lot Mixed Brass WLP (brass) OAL 1.250" taper crimp .469"

16-May-09 high 83 °F .

Ave Vel = 805.2
Std Dev = 38.07
ES = 136.9
High = 912.4
Low = 775.5
N = 24





230 gr LRN Valiant 4.5 grs Bullseye lot 827 (60's/70's powder) Mixed Brass WLP (brass) OAL 1.250" taper crimp .469"


16-May-09 high 83 °F

Ave Vel = 822.9
Std Dev = 14.14
ES = 55.24
High = 853.7
Low = 798.4
N = 26

[Unclenick]

If I understood the OP, he got an abrupt increase in elevation in the range of 4.0 and 4.2 grains that was not there for any load from 4.5 grains to 5.2 grains, and not a transition in proportion to the load change. Shooting revolvers, where the mechanics are more constant, I see elevation change with charge that is gross at long range, but up close is comparatively minor. Certainly smaller than I get from changing bullet weights at that same range.

Jector,

There used to be an animated 1911 image on line that was pretty clear. I'll have to see if I can find the link?

This is (http://rds.yahoo.com/_ylt=A0oGkx8Vxc9KKXkAGFNXNyoA;_ylu=X3oDMTBydHRjbmRzBHNlYwNzcgRwb3MDMwRjb2xvA3NrMQR2dGlkAw--/SIG=12i7h7o7g/EXP=1255216789/**http%3a//www.youtube.com/watch%3fv=YKRMcTlbWTs%26feature=related) not the one I had in mind, and it waits too long for recoil to start to register in the slide, but it shows the basics.

OK. This is better (http://www.m1911.org/full_1911desc.htm) and more complete. I used to post in their forum, but hadn't visited for awhile.

Nick

[LHB1]

Quote: "If I understood the OP, he got an abrupt increase in elevation in the range of 4.0 and 4.2 grains that was not there for any load from 4.5 grains to 5.2 grains, and not a transition in proportion to the load change. "

Quote: "I found, except for my 4.2 gr of Bullseye test load, all my loads above 4.0 gr hit lower at 25 yds than my 4.0 load. I went all the way up to 5.3 grs."

I got a different reading. I understood that all loads above 4.2 gr hit lower than the 4.0 and 4.2 gr loads. Which, to me, simply says the faster loads hit lower because they were out of the barrel before it raised as high (recoil) as when firing the 4.0 and 4.2 gr loads.

[plainsman456]

+1 on the out of the barrell faster doing this.Good Luck

[Jector]

Unclenick. TYVM it was educational.

[crimsondave]

Just got back in. Belated thanks to all for your replies. Makes sense. The 4.0 load is pretty tight (for me, 3-4" at 25 yds is about as good as I can shoot a pistol) and is pretty close on my factory sights. I wish I had adjustable sights on my Kimber as I'm hitting about 1" to the right, but no biggie.

[LHB1]

Quote: "I wish I had adjustable sights on my Kimber as I'm hitting about 1" to the right, but no biggie. "

Most non-adjustable rear sights can be tapped left or right in the slide groove. Problem is that Kimber sights have a reputation for fitting VERY tightly and are not easy to move. May require a sight pusher tool from Brownells or gunsmith attention to tap your rear sight to the left. At what distance are you shooting when it is hitting 1" to the right? This distance will affect the amount of adjustment needed.

[crimsondave]

"Most non-adjustable rear sights can be tapped left or right in the slide groove. Problem is that Kimber sights have a reputation for fitting VERY tightly and are not easy to move. May require a sight pusher tool from Brownells or gunsmith attention to tap your rear sight to the left. At what distance are you shooting when it is hitting 1" to the right? This distance will affect the amount of adjustment needed."

25 yds.

[LHB1]

Yea, 1" at 25 yds would be a very small adjustment. I wouldn't try to correct that small an error by tapping/moving a fixed rear sight. That's why I prefer adjustable sights on most of my pistols (except for CHL carry guns).

[crimsondave]

Next time I shoot, I'm gonna try lining the front sight up flush with the left side of the back sight instead of centering it. That will prolly put it dead on.