Grand Power Chronograph Results - Norma, Federal, Hornady etc.

[spencerhut]

Got around to shooting a few of my collection of vintage loads over the chronograph with my 4.25" Grand Power. The temp was in the mid 30's where I live today. The CED M2 chrono screens were set 15" from the shooting position. All numbers are based on a minimum of five (5) good shots over the screens.

Sorted by USPSA Power factor, higher is more better.



I had one or two times where the mag dropped out of the gun the first time I shot it. I thought I was over that but it started happening again today. Seemed like the more stout loads were worse than the lighter loads. The magazine self disassembled once and scattered ammo and parts all over in the snow. It was sort of comical. My wife who has child sized hands shot the Grand Power with some of the light Federal loads and liked it. Not so much with the 170g Norma's.

Overall I was disappointed with just about all of these loads. None seemed all that powerful to me, not even the Norma's.

Compared to some of my .40S&W reloads and a factory Corbon load these results were sort of lame.


Some .45ACP loads for comparison

[Intercooler]

I think it's 4.25" barrel for P40. The GP Chrony numbers come in even lower than some 4" barrels.

[sqlbullet]

Got around to shooting a few of my collection of vintage loads over the chronograph with my 4.5" Grand Power.

...

Overall I was disappointed with just about all of these loads. None seemed all that powerful to me, not even the Norma's.

In general the 10mm ammo available in the '90's was pretty weak sauce IMHO. After the FBI reports came out it seemed like everyone decided that 400-500 lb ft of energy was plenty and they weren't going to load beyond that.  Add in the issues the early DE had with frame cracking and everyone was afraid the 10mm at full power was just too much for most handgun platforms.

Luckily today we know that the Glock, Witness, Sig, and GP, as well as a properly built 1911 will hold up to full power 10mm for a long time.

[spencerhut]

I think it's 4.25" barrel for P40. The GP Chrony numbers come in even lower than some 4" barrels.

Yup, brain fart. I'll fix it.

Thanks!

[PCFlorida]

So how has the GP been for you? Still having problems with the magazines dropping?

[spencerhut]

So how has the GP been for you? Still having problems with the magazines dropping?

See my post in the main pistol forum

[PCFlorida]

So how has the GP been for you? Still having problems with the magazines dropping?

See my post in the main pistol forum

So it sounds like you are GTG now, good deal! Since I had the problem at one time and then no more since I will send mine in for the newer magazine catch / release. Thanks for the follow up.

[PCFlorida]

So I got mine back two weeks ago. That is a strong mag catch, but it functions!

[spencerhut]

I did not notice any change in pressure to, but it holds the mags just fine now.

[PCFlorida]

I did not notice any change in pressure to, but it holds the mags just fine now.

Good to hear.

[GoldBead]

It is astonishing to me that Winchester isn't sued either for false Advertising or fraud. No chrono test I have ever seen has the factory silvertip shooting even close to 1290.

It would be the top stock factory hunting/self defense load, if it performed, but six inch barrels don't show 1200 fps and out of my 16 inch subgun, the load is sad. Compared to the Underwood 135, which exits at 2050, giving an energy close to 1220 ft/lbs and is my 10mm subgun standard load.

The bullet is great, I just wish the bullet was pushed to Winchesters advertised velocity.

[sqlbullet]

The factory ammo master sheet here shows Intercoolers test from a 4.75" witness barrel at 1210 fps.

A SAAMI spec barrel is just a touch longer, but will also have a machinist cut minimum chamber and have minimum headspace.  In addition it will have a six groove barrel cut to minimum spec.  All of these factors will raise pressure and correspondingly raise velocity.

This is why SAAMI participating ammo producers have velocity numbers that people often question.  The purpose of the information is not to convey what you should expect to see in your sloppy tolerance production gun.  It does accurately test pressure in a "worst case" barrel that is still in spec, and it provides a standardized common reference for comparing different ammo makers loadings.

Is the Winchester Silvertip downloaded?  Yeah...just a bit.  SAAMI spec max velocity from a minimum chamber/headspace 5" test barrel for 170 grain ammo is 1320 fps nominal mean measured 15' from a test barrel.

Which is another item that often gets overlooked.  SAAMI produces both a pressure specification AND a velocity specification.  "Spec" ammo conforms to both numbers.  With modern powders can we get past 1320 fps in a minimum chamber/headspace while still conforming to the pressure specification?  Yeah, we certainly can.  Will the ammo be safe in modern guns?  Yeah, almost certainly will. 

But...when was the last time you heard of a Ka-Boom with Silvertip ammo?  Not saying they don't happen.  I know of one report with a Colt DE.  But we are all surprised when we hear this about Winchester ammo.  Double Tap, Buffalo Bore, Underwood?  Not so much surprise.

Winchester doesn't get sued because the advertised value can be easily duplicated using a SAAMI spec pressure barrel in correct laboratory conditions.  These conditions are designed to represent stacked minimum tolerance, or real world worst case, chamber and bore.  These conditions produce higher pressures, and correspondingly higher velocities than most users will encounter in the real world with the ammunition.

[Intercooler]

  The data shows it has changed several times over the years concerning powders, amounts and velocities. I don't doubt it flew at 1290 FPS in their stated barrel length at some point in time.