.45acp Corbon and Golden Sabre Underpowered???

J

J.T.King

New member
Hello!

I just got back from a trip to Lake Tahoe where I did a bunch of reloading with my father. He has a new Pact One chrono which we used to test the reloads in addition to the two factory loads that I use for Self Defense.

All loads were clocked out of a H&K USP45f with the chronograph at about 6 feet away.


**** NOTE! THE CORBONS WERE 230GR, NOT 180GR!! ****
The Corbon 185gr JHP is listed by Corbon at 1150fps. Over a string of five shots I recorded the following:
Avg Velocity: 958fps
Std Deviation: 10.7
Hi Velocity: 967
Lo Velocity: 940
****** THIS DATA IS RIGHT ON THE MONEY!!!****

The 230gr Remmington Golden Sabre JHP is listed at 875fps. Using a string of five random bullets I got:
Avg Velocity: 808fps
Std Deviation: 15.7
Hi Velocity: 831
Lo Velocity: 787

Now my question is this... Why so low??? I suppose that the chrono being 6 ft away could impact it, but by almost 200fps (Corbon)??****NOTE! The Corbon's were RIGHT, my butllet size was off.

I also suppose that the Chrono could be off, but when I ran up my own reloads the numbers clocked right in line with most of the Reloading manuals's estimates. Also, my father's 147gr 9mm Golden Saber's clocked at 1005fps, very close to Remmington's 990fps listed velocity.

Needless to say this gives me great pause about my Self Defense ammo selection. I know, I know, placement is everything, and believe you me I work quite hard at that! But self defense is a lot about confidence in your equipment and your ammunition and I have to say I am disappointed.

Anyone else had this experience?

Opinions?

What should I be looking at now?

Thanks!

J.T.King




[This message has been edited by J.T.King (edited August 09, 2000).]
 
You may just have a slow gun, if I can remember correct Cor-Bon 185gr +P Averaged 1102fps from my Sig P220 which has a shorter barrel than your HK.
 
Being someone who owns a USP45F, I would not think of it as a 'slow gun'. The USP's have a polyagonal barrel which is designed to increase muzzle velocity over what a standard riffled barrel would. I find that pretty interesting regarding the numbers though. That's a very significant drop.

Evan
 
J.T. - what is the barrel length of the USP45F? And does Corbon state the barrel length of their test gun? A couple of inches difference in length could account for the discrepancy.

The next time you get the chance, maybe you could fire some known velocity rounds over the chrono to check it. Usually the premium .22LR's are an excellent calibration round on the low end (e.g., Federal 900B or 1000B). 6 ft. from the muzzle should only yield a higher MV, not lower. Most check the MV at 10 to 15 ft. so as to eliminate the gas pulse effect. In fact you might try a longer distance for your next go 'round. You might be tripping the front sensor with the supersonic gases and then tripping the back sensor with the bullet. That would yield an apparent lower velocity. That does happen.
 
Do remember that all factory velocities for ammo are usually given from a test barrel, at sea level, at a specific atmospheric pressure, ad nauseum. There are numerous factors that influence cartridge performance, not the least of which is temperature, altitude, and even bullet age.

How old were these rounds? What temperature/altitude were you shooting at?

I once clocked some Wal-Mart special 125gr JSP from UMC from a S&W model 686 at 1,680 fps. Ambient temp was about 95 degrees and we were at about 6' aboe sea level. The published velocity is only 1450fps.
 
There are a myriad of things that can affect velocities, but those numbers are indeed surprisingly low. Our box velocities are from a 5" bbl on a 1911a1 pistol, the standard 45ACP test length. Guns are for sure fast or slow, just like people...but that sounds too low. Call me here at the plant; let's talk about this. The # is on the ammo box. Have that box with you so i can check lot numbers etc. THANKS!TM
 
Many things can effect velocity; Air Pressure and Altitude and Humidity etc.
These things could have been factors.

OR

That box of Cor-Bon could have actually been 230 grains. If those were 230s - those numbers would have been spot on.
 
True, George.

My friend normally chrono'ed 187-193PF, but at the AWARE he got 176PF, and at the Limited Nationals it was even lower.
Same gun (45ACP), powder, primer lot, same box of bullets.

Some ammo (45ACP) I made for guy normally goes 188PF, but at the AWARE (hot and muggy) it only went 167PF!

(My gun, a 9x19, made its normal 139PF. Hmmm)...

------------------
"All my ammo is factory ammo"
 
Hello!

First off:

*** MY BAD!!! THE CORBONS WERE 230GR!!! ***

Appologies all the way around. I *had* 185 grains but I apparently shot them all up last time up there and this was some 230gr left hanging around. My appologies to Corbon, your product performed admirably and to spec. :[

Kudo's to ARM USA in Anaheim, CA for looking up my receipt from March to verify the bullet size when my brain got fuzzy.

Mal:
The barrel length of the HK USPf is 4.41 inches. This might acount for a drop in velocity on the Golden Sabers.

Also, we DID shoot a "known" velocity round through the crono. My father's 147gr 9mm Golden Saber's. The clocked (avg of 5 bulets) 15fps higher than spec.

I did have one "gas trip" on an earlier run of my own reloads, but I was shooting at about 4 ft away. It was pretty obvious tho. On a 900fps string one came in at 650fps. Since I had very consistent results on the Factory Rounds and the front sensor was at least 6 ft from the muzzle, I doubt that was what it was.

Chad:
I was at Carson City, NV (3500ft? 4000ft?) with not a nit of humidity and the temperature was 80-85 degrees F.

I guess then my lingering doubts center around the Golden Sabers, not the Corbon. With the Corbon coming in 8fps higher than their spec, why did the Golden Saber come in almost 60fps low (avg)?

Again, my appologies to Corbon and congrats on a perfect product.

Anyone else on the Golden Saber question?

J.T.
 
You may assume R-P's velocities were developed in a test barrel.

Please, do not expect published velocities to be correct for your specific individual gun. Testing will reveal how your personal gun performs.

I've tested multiple matching pairs of guns with zero variable other than the guns themselves.
Closest was 30fps, largest variance was over 100fps.
Just for fun read the Speer manual "...but not always..." article.


J.T.,

I do not consider a 230g bullet at 800fps to be "underpowered". (I don't consider my 230g GS load at 972fps to be "overpowered" either LOL)

------------------
"All my ammo is factory ammo"
 
ALL'S WELL THAT END'S WELL. IF THAT IS YOUR WORST MISTAKE THIS YEAR YOU'LL HAVE A DOOZY OF A YEAR. IF ALL YOU FOLKS HAVE QUESTIONS ABOUT CORBON'S PRODUCTS NEVER HESITATE TO CALL ME HERE AT THE PLANT. AFTER ALL, I GET A PAYCHECK TO TALK GUNS AND AMMUNITION ALL DAY LONG TO GUNNERS ALL OVER THE WORLD. AWFULL JOB BUT SOMEBODYS' GOTTA DO IT...
Oh damn, I forgot the caps again; it's 'cause all us old gunners are deaf as posts and yelling is normal conversation.

[This message has been edited by TERRY MURBACH (edited August 10, 2000).]
 
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