I chrono'd some Double Tap 200 grain hard casts from a Glock 20 4.6 inch today and I got an average of 1210fps @ 15 feet. This is above what is documented in the ammo sheet but still well below the advertised of 1300fps. Just an FYI that he might be loading these hotter now. I also shot one into wet books and it penetrated 23 inches, which would probably translate into 30+ inches in ballistics gel. No visible deformation after all that penetration, but it lost 5 grains somewhere. I pulled another one from a fresh cartridge to verify and it was indeed 200 grain.

Did you weigh the powder charge to see how much was used?  More than likely it was LongShot powder.

No, I'll try to remember to do that tomorrow.

1210 is pretty good. I think 1300 always has been a lie. For a good while I've seen this chronod in the 1100's so this is pretty good. I still have about 20 of these from 2009, hopefully it wasn't during the downloaded phase he was in.

they "felt" solid in my G20, but don't have a chrono.  I've also never had one mis-feed or not go bang.  For those reasons alone it is my woods carry load.

As long as they are accurate in your barrel, that is a pretty good bullet. Maybe one of the best designs out there in the 10mm heavyweights. Nothing wrong with a 200gr @ 1200 fps!

Quote from: The_Shadow on May 08 2014 03:02:09 PM MDT
Did you weigh the powder charge to see how much was used?  More than likely it was LongShot powder.

8.3 grains.

That's very close to the 8.2 grains I measured from Double Tap 200gr Wide Flat Nose Hard Cast Gas Checked the "Pull-Downs".

Were your's gas checked? 

Quote from: The_Shadow on May 09 2014 08:59:46 AM MDT
That's very close to the 8.2 grains I measured from Double Tap 200gr Wide Flat Nose Hard Cast Gas Checked the "Pull-Downs".

Were your's gas checked? 

Yes.

And they still sure do lead up the barrel....

I chronographed some more of these....

High: 1120
Low: 1054 
Avg: 1090

These seem to be very inconsistently loaded. Maybe my 1210 average a couple months ago was just a fluke.  :'(

Did the Double Tap 200gr Wide Flat Nose Hard Cast have the Gas Checks?  Did you get a measurement on their diameters?

If they are at 0.400", yes the will lead the bore, because they will be too small in diameter, People were seeing keyholing with the smaller diameters from the Glock factory barrels...that could account for the lower velocities with the blow by.

0.4015" is what I found to keep the leading down in the Glock factory barrels and others recommend 0.4020".

Yes they have gas checks. No keyholing. Accurate from both Glock and KKM barrels. Haven't gone further than 20 yards.

Bullet at widest lead point measures .395 and .390 at the gas check...

EDIT: All my other .40/10mm bullets measure .400 or .401 or .402.

I have not chronographed from the KKM barrel. I should do that next time.

At those measurements they are quite small and would explain the leading.   

Could loaded ammo be measured at the brass lip? Would that be its widest point? I have some 200gr loaded ammo that I would like to measure.

Radiotom - can you measure what the COAL is on those factory loads?  Trying to dial in my reloads with those bullets and as you know at 1.250" they don't feed 50% of the time.