Why Low Velocity from 45 1911?

[lbmii]

This month's issue of American Rifeman had a report on the Mitchell's Mausers Gold Series 1911 45 auto. The velocities listed were very low.

Black Hills 230 FMJ = 677 fps
Hornady 180 JHP = 874 fps
Speer 200 GDHP=793 fps

Why such low numbers from a full 5 inch barrel pistol?

This was from a 5 inch barrel. The velocities given above are much lower than velocity tables for the 45 ACP. Just going by my memory, the 230 should be about 830 FPS and the 180 should be about 1000 FPS.

I ask those of you that have measured 45 ACP velocities. What sort of numbers do you get from your 45?

 

[Jim Watson]

I read the same article and noticed the same low velocities.
Why?
I don't know why, but I do know what.
I dug through some back numbers of American Rifleman and found other .45 ACPs. Unfortunately they don't stick to the same test ammo but I found:

Dec. '04 Black Hills 230 FMJ - 677 fps in Mitchell.
Aug. '04 Black Hills 230 FMJ - 848 fps in USMC Kimber

Apr. '04 Black Hills 230 GD - 820 fps in SA GI
Mar. '04 Black Hills 230 JHP - 838 fps in Sigarms GSR
Dec. '02 Black Hills 230 JHP - 828 fps in Brown Kobra

I didn't go to the effort to tabulate all brands and try to get other matchups, but it looked like other .45s tested in the last couple of years all gave close to standard velocity for the loads tried.

So what happened this time?
Bad batch of ammo? (THREE bad batches of ammo?)
Bad chronograph? (The .17 and .22 in the same issue didn't look slow.)
Funny barrel from Mitchell?

I dunno, but note that none of the three brands tested made Major Power factor for IPSC or IDPA competition, which seems to be what this model is intended for. That could be an unpleasant surprise to the buyer when he took it to a big match and got chronographed.

 

[stans]

Velocity that low would either be a typographical error or a bore that is a little oversize.

 

[Jim K]

Not only does velocity differ from gun to gun and round to round, but testing methodology can make a big difference.

One of the most common reasons for different readings is that the chronograph was set up differently or a different chronograph used. It is pretty common to set the chronograph at, say, 50 feet, but forget to extrapolate the results back to get the (approximate) muzzle velocity.

As to comparison with published data, it is pretty well known that many published "ballistics" tables are really "bullistics" tables.

It is also a good idea to read the article and picture captions (if any) carefully. I recall one magazine article bragging about the accuracy achieved with the test rifle and showing dime size groups. The writer never mentioned the distance and hinted that it was 100 yards, but the pictured target betrayed him - "25 yds" was written on it.

Jim

 

[Dave Sample]

Bad barrels are common is these kind of 1911's. 100 FPS would be about the maximum difference due to weather and tempature.

 

[1911Tuner]

Chronograph

Could also be a simple matter of instrument calibration. Different conditions can cause varying results from one day to the next with a given load and gun,
but if the chronograph is outta whack, it can drive ya over the top.

I had that happen once. Testing some .45 ACP loads turned in some frighteningly high velocities with heavy bullets...250-grain...and I considered
not firing the rest of the lot because of it. Then it hit me to test-fire a known lot of 230 ball equivalent reloads to see what those results would be.
When I was rewarded a few near-44 magnum numbers on the screen, I knew that I had a chrono problem. It could easily have gone in the other direction.

I've also discovered that chronographs are not to be completely trusted to
tell you anything except to give you a comparison between two loads and an idea of the consistency of a given load. I tend to take any reading that I get
with a portable chronograph with the attitude..."Okay. If you insist."

 

[Jim Watson]

Well, I'm going to write NRA.
They recommend the gun for IDPA or IPSC and for whatever reason of gun, ammo, or chronograph, in no case did it deliver Major Power Factor as required for IDPA CDP or for Major scoring in IDPA Limited.

If Mitchell is routinely using "slow" barrels, they are setting some customers up for a fall.
Or NRA is not keeping their facilities in order.

 

[Black Snowman]

If they were using a "Chrony" and it had been damaged so it could open further than normal it would created lower than actual numbers. If a Chrony isn't opened all the way they clock slightly faster. Could be a combination of factors, including cold weather, altitude, calibration, etc . . . all "stacking" against the numbers. Or just a sloppy barrel.

Only way to know is to have been there and recorded all of the relavent information. Slugged the barrel, etc . . .

 

[Jim Watson]

Lord, I hope the NRA can afford something fancier than a Chrony.
I sent them an e-mail inviting comment.

Like I said, you show up at an IDPA or IPSC match big enough to be chronographing competitors with a .45 shooting hardball at 677 fps, PF 155, you are in a world of hurt. If it were me, I would be right ill with Mitchell. And the NRA for recommending it.

 

[baker]

Dan Wesson is building the gun for Mitchell, and I haven't seen any data to indicate slow bullet performance in their other products of similar date and build.