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.40 S&W ammo test
buschmaster
Member Posts: 14,229 ✭✭✭
on the other topic about .40 kabooms, the information I was coming up with said the .40S&W is sensitive to bullet setback. if it is pushed into the case more than 1/10" it may go overpressure. (or 1/32" for hot loaded ammo)
http://forums.GunBroker.com/topic.asp?TOPIC_ID=655153
well I was looking at a .40 round, the distance from the case mouth to the angle on the bullet measures 1/16".
1/16 is less than 1/10. so as long as the angle part isn't pushed all the way down to the case mouth, no problem!
(or halfway for the hot loaded ammo)
like that's ever going to happen.
supposedly, setback occurs from chambering a round too many times. the feed ramp pushes on the bullet, and so does friction from the chamber. sources said any more than once or twice is enough to cause setback.
really?
so I took 3 types of ammo, 1 cartridge each, and cycled them 100 times to see how much setback we get.
1. load the 3 rounds into magazine
2. insert magazine
3. rack slide until all rounds ejected
4. repeat 99 more times
THE AMMO
Fiocchi "Shooting Dynamics" 165 gr. JHP
Sellier & Bellot 180 gr. FMJ
Herter's Select Grade 180 gr. FMJ
just so you know, Herter's Select Grade is made by S&B. Fiocchi uses Starline brass.
hey let's talk about ammo a little bit. Winchester White Box costs $33 for 100 at China-Mart, but the Herter's costs 17$ for 50 at Cabela's. that's $34 for 100. spend a buck more and get better ammo! what a deal! the Fiocchi was $24 for a box of 50 at Cabela's, while the other JHP whiz-bang ammo was $24 for boxes of 20. ah, I think I'll take the Fiocchi. it's not their Extrema series but it must be good enough coming from those guys.
headstamps
L-R: Fiocchi, S&B, Herter's
before the test the Fiocchi already looks a little setback.
after the test:
1. Fiocchi unaffected
2. S&B went down halfway (1/32")
if this would have been hot-loaded ammo, it would be at the limit where overpressure may occur.
3. Herter's unaffected
check with a ruler:
leaving the Herter's out of the picture, here is a closeup of the Fiocchi and S&B so we may further scrutinize the effects.
new cartridges in the middle, tested cartridges to the outside.
CONCLUSIONS:
1. you should be able to detect setback by eyeballing it.
2. cycling your .40 ammo once or twice isn't going to do anything.
http://forums.GunBroker.com/topic.asp?TOPIC_ID=655153
well I was looking at a .40 round, the distance from the case mouth to the angle on the bullet measures 1/16".
1/16 is less than 1/10. so as long as the angle part isn't pushed all the way down to the case mouth, no problem!
(or halfway for the hot loaded ammo)
like that's ever going to happen.
supposedly, setback occurs from chambering a round too many times. the feed ramp pushes on the bullet, and so does friction from the chamber. sources said any more than once or twice is enough to cause setback.
really?
so I took 3 types of ammo, 1 cartridge each, and cycled them 100 times to see how much setback we get.
1. load the 3 rounds into magazine
2. insert magazine
3. rack slide until all rounds ejected
4. repeat 99 more times
THE AMMO
Fiocchi "Shooting Dynamics" 165 gr. JHP
Sellier & Bellot 180 gr. FMJ
Herter's Select Grade 180 gr. FMJ
just so you know, Herter's Select Grade is made by S&B. Fiocchi uses Starline brass.
hey let's talk about ammo a little bit. Winchester White Box costs $33 for 100 at China-Mart, but the Herter's costs 17$ for 50 at Cabela's. that's $34 for 100. spend a buck more and get better ammo! what a deal! the Fiocchi was $24 for a box of 50 at Cabela's, while the other JHP whiz-bang ammo was $24 for boxes of 20. ah, I think I'll take the Fiocchi. it's not their Extrema series but it must be good enough coming from those guys.
headstamps
L-R: Fiocchi, S&B, Herter's
before the test the Fiocchi already looks a little setback.
after the test:
1. Fiocchi unaffected
2. S&B went down halfway (1/32")
if this would have been hot-loaded ammo, it would be at the limit where overpressure may occur.
3. Herter's unaffected
check with a ruler:
leaving the Herter's out of the picture, here is a closeup of the Fiocchi and S&B so we may further scrutinize the effects.
new cartridges in the middle, tested cartridges to the outside.
CONCLUSIONS:
1. you should be able to detect setback by eyeballing it.
2. cycling your .40 ammo once or twice isn't going to do anything.
Comments
Maybe some of the problems with 40's kabooming comes when people cycle the round they have in the chamber every day. They CCW the piece loaded and when the come home eject the chambered round and put it aside. the next day they load it back in the chamber and away they go. Then at some point in time they go to shoot their old carry ammo and KaBOOOM!.
I always alternate my round that is in the pipe. When I was in the army we were told to re-chamber a new round every morning(From the magazine). The round that was in the chamber had been subjected to oils and moisture(How much more than the rounds in the mag I don't know)but that is the way I was trained and for 25 years I did just that and I still do it with my carry piece.
I always reload 40 S&W with a tight crimp, make certain that the loads are compatible with the gun in which they are to be fired, & that along with a fully-supported chamber, the rounds glide smoothly up the ramp and into the chamber.
I also use a caliper instead of a tape measure when determining critical measurements.
But hey, if ya wanna pay exhorbitant prices for ammo made so rapidly that the bullet slides back into the case; have at it.
I think I remember reading about replacing every morning in a Viet Nam "accumulated knowledge guide". I think they said it was due to condensation. whichever, it probably was a good idea.
I don't think any rifle cartridge will be sensitive to setback, having larger case volumes.
next I would like to get a micrometer and check the OAL of a bunch of different ammo, and Federal to see if it is seated deeper.
if so, that would tell me if the Fiocchi might have problems like Federal. because that does appear to have a deeply seated bullet from the factory.