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Underwood 220 gr hardcast

22K views 33 replies 23 participants last post by  nickE10mm 
#1 ·
I'd been waiting for this....although I'm not sure I thought I would see a 220 grain....velocity seems outstanding....hmmmm....
 
#27 · (Edited)
Wanted to get some chronograph results and see how the Underwood 220gr hard cast works in a Glock 29.

I decided to compare the spread of hits of the 220gr HC between my 1911 with its Bar-Sto barrel and my third generation Glock 29. The G29 is standard, except for a metal recoil rod assembly with a standard 17lb recoil spring.

I placed the target at 30 yards and shot slow strings with my hands resting on a shooting bag. Took lots of time to make sure my sights were aligned consistently. Each square on the target is 1x1". The group in the upper left is from the Glock. The better centered group is from the 1911. Proves in my mind that the Glock barrel does stabilize the 220gr ammo. Then I shot the Glock at a distinguishable formation on a berm about 60 yards away, standing off-hand. The hits were comfortably close to the target, showing again, the bullets stabilize.

Here are the chronograph results

Altitude: 3221 ft, Temperature: 48 degrees, Barometric pressure: 26.9 inHg

10mm Underwood ammo -

Glock 29

180gr XTP : 1263, 1266, 1255, 1253, 1299 : avg 1267 ft/s
200gr XTP : 1133, 1120, 1141, 1153, 1170 : avg 1143 ft/s
220gr HC : 1075, 1082, 1084, 1104, 1094 : avg 1088 ft/s

1911 4.25" Barrel

180gr XTP : 1271, 1265, 1269, 1299, 1253 : avg 1271 ft/s
200gr XTP : 1181, 1187, 1199, 1183, 1167 : avg 1183 ft/s
220gr HC : 1152, 1153, 1165, 1156, 1161 : avg 1157 ft/s

Target attached:
 

Attachments

#28 ·
10mm Underwood ammo -

Glock 29

....
220gr HC : 1075, 1082, 1084, 1104, 1094 : avg 1088 ft/s

1911 4.25" Barrel

....
220gr HC : 1075, 1082, 1084, 1104, 1094 : avg 1087 ft/s

Target attached:
Was one of these a cut and paste gone bad? They are exactly the same...(well except for your calculation of the average :D)

BTW I just got some of the 220 HC in the mail, it's back in stock (as of last week anyway).
 
#31 ·
Does anyone know if Underwood is using a stock barrel to achieve his chrono results? 220gr@1200fps out of a 4.6" barrel is outstanding.
My GUESS would be 800X... but possibly Longshot.
 
#33 ·
Underwood uses a 24# spring...he told me. He shoots hot all the time, so I'd imagine. I use a 22# SS rod/spring. Works great in both worlds.
Enjoy!
DT does as well. It gives a few more FPS as the extra weight delays the unlocking a fraction of a fraction of a second. When I shot alot of hot 10mm I found 21# (G29) and 22# (G20) were plenty for the most powerful loads. The 24# G20 and 23# G29 springs returned diminishing results in my experience. Lighter springs really do result in less recoil, especially muzzle flip but more frame battering. There is more battering when slide go's back to battery with heavier springs though. If stock is 17-18#, a 22# spring is 20-25% heavier. Plenty for two well-designed pistols with very heavy slides by any standards.
 
#34 ·
DT does as well. It gives a few more FPS as the extra weight delays the unlocking a fraction of a fraction of a second. When I shot alot of hot 10mm I found 21# (G29) and 22# (G20) were plenty for the most powerful loads. The 24# G20 and 23# G29 springs returned diminishing results in my experience. Lighter springs really do result in less recoil, especially muzzle flip but more frame battering. There is more battering when slide go's back to battery with heavier springs though. If stock is 17-18#, a 22# spring is 20-25% heavier. Plenty for two well-designed pistols with very heavy slides by any standards.
Spot on, I agree. A little increase in spring weight is appropriate but nothing overkill.

I use a 20lb spring for NUCLEAR loads in my 6" Fusion and had a 20-22lb spring in my G20 and they are or were both perfect.
 
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