9x25 Dillon vs .357 SIG

[Overkill338]

I got a 9x25 conversion barrel for my G29 that's the stock 3.8". I watched a YouTuber get 1550 fps from Underwood 9x25 124gr ammo. But people get around 1510 fps with a Glock 32 using Underwood .357 SIG 125gr. Did I mess up going with the 9x25? Or would I have been better using a 3.8" 357 SIG barrel. I know I'm missing nearly a 1/4" compared to the G32. But I'm starting to think I've gotten myself extra blast noise, fire balls, and more $ for ammo for nothing.

Edit: Found another test, same 357 SIG Underwood Ammo from a G33 (3.42" barrel), it got 1392 fps.

[The_Shadow]

With these two cartridges everything is a factor...Bullet and powder and even barrel lengths but how people take readings from the chrony is another factor all its own...

[Pablo]

Everything being correct and right, for sure a 9x25 is faster. You chose fine. Next spring get a 357Sig barrel. I have both, join the club.

[The_Shadow]

From my two 3.78"barrels the 357Sig gets 1350-1400 fps with most 125 grain bullets and the 9x25 Dillon is 1550 fps using LongShot. 
Got some nice numbers from AutoComp and CFE Pistol in 357Sig but haven't tested the 9x25's in the 3.78" barrel yet.

[sqlbullet]

What is it the muscle car guys say:  "There's no replacement for displacement!"

Same applies here.

More initial case volume means a flatter pressure curve, and that means more velocity. It's physics and there is no free lunch.  Anything the 357 Sig can do, the 9X25 will do about 15-20% better.

The difference between a 124 grain bullet and a 125 grain bullet can be VERY large.  It is more than a grain of weight.  There is bearing surface, jacket material, nose profile quality of construction, all to consider as well.  All these things can add up to a lot of difference in when you reach SAAMI max.

If you want easy to find ammo, then 357 Sig would be a better choice.  But if you want the best performance in a 9mm handgun round, 9X25 is where it's at.

[Overkill338]

Thanks guys. First I've got to get the chronos bullet wound fixed lol

[BEEMER!]

I like sqlbullet's car analogy.

My question is the Sports Car that goes 200 MPH better than the one that goes 180?

I guess it is all in what each individual wants.

[sqlbullet]

I like sqlbullet's car analogy.

My question is the Sports Car that goes 200 MPH better than the one that goes 180?

I guess it is all in what each individual wants.

I was thinking more top fuel, which is kinda what this really is.

Every choice is a compromise.  Fastest car?  Depends...Fastest from where to where under what conditions.

Top Fuel is fastest for a 1/4 mile in a straight line.

Track and road course, I think Indy Car are about the fastest these days, though F1 may be more competitive on certain track types.

Offroad for 1K miles...Look to a trophy truck.

And none of these would be a good choice for back and forth to the office for twenty years.

But if you are after speed...nothing matters more than case capacity.

[The_Shadow]

Yes it can be a Top Fuel Cartridges in both, but keeping it real can be great fun too.  When I started with the 9x25 Dillon it was with the S&W 1006 and a Bar-Sto 5" Match Grade barrel which is very unique to that series of pistols.  The with the G-29 I bought the 9x25 and 357 Sig barrels for play time and experimentation.  Although the 5" barrels performed well, it wasn't until I went with the G-20 with a 6" that the velocity started to show its true self! 

Being a handloader and bullet caster, it was just another way to put lead on target. 

[my_old_glock]

I got a 9x25 conversion barrel for my G29 that's the stock 3.8". I watched a YouTuber get 1550 fps from Underwood 9x25 124gr ammo. But people get around 1510 fps with a Glock 32 using Underwood .357 SIG 125gr. Did I mess up going with the 9x25? Or would I have been better using a 3.8" 357 SIG barrel? I know I'm missing nearly a 1/4" compared to the G32. But I'm starting to think I've gotten myself extra blast noise, fireballs, and more $ for ammo for nothing.

Edit: Found another test, same 357 SIG Underwood Ammo from a G33 (3.42" barrel), it got 1392 fps.

http://10mm-firearms.com/general-discussion/i-guess-i'm-getting-the-9x25-dillon-barrel-after-all/msg64304/#msg64304 





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[The_Shadow]

More than likely those were the same as the Underwood 357Sig pull-downs which were loaded with 10.0 grains LongShot.
http://10mm-firearms.com/factory-ammo-pull-downs/underwood-357sig-125gr-bonded-fmj-pull-down/

Olgo, did get some newer 9x25 from Underwood, it would be interesting to see what is in those with 125 FMJ @ 1700 fps...