9x25 Dillon subsonic, am I crazy?

[Longranger44]

It seems like a lot of work compared to just having two barrels.

Two barrels? I don't trust the reliability of a 9mm in a slide designed for a 10mm case head if that's what you mean

[Longranger44]

A couple thoughts, the 357 Sig would be better choice for subsonic with better powder density. Running longer cases and small powder charges of faster powders in a longer case can cause some weird shot to shot and could be powder position sensitive. I would also look at 165gr and heavier bullets for subsonic. If you are wanting the best of both worlds subsonic/ super sonic in a pistol length barrel I am not sure there would be a huge velocity difference between the Sig and 9x25 Dillon?
Lastly you might need to also open up the throat on both since most reamers are tight on the throat.
As to what gun, if it were me doing this I would use a G20 this way I could build both calibers on it.

I think you're right about the velocity difference in a standard g20 length barrel but I'm planning on doing a G20L and with the extra length it appears that the 9x25 has about a 200 fps advantage.

Good info on the smaller charges in a bigger case... But I'm wondering if I'd run into bullet jump issues with the heavier bullets, and I doubt there are any 355 or 357 165 or 180gr hollow points that are designed to expand at subsonic speeds... I think you're definitely right the 357 sig is by far more practical as there are factory subsonic loads (one from doubletap anyway) and starting 147gr loads are pretty much all subsonic from what I've seen. 357 sig also has the advantage of being able to use a $120 lone wolf instead of a $400 bar sto. The downside is the cool factor I'm a sucker for unique **** that's not necessarily the most practical, I like having what no one else has

[475AR]

I understand the unique thing, I am running a G20 with a 6.6" barrel chambered in 45 Gap and to top it off I run 250gr and 300gr bullets and it is accurate and suppresses very well.
But back to the issue at hand, there are companies like Maker bullets and others that make solid copper subsonic bullets in 35 caliber but being you are looking to use a Glock platform you will be limited to what COL the magazine will allow and feed without issue. If you are looking for expanding bullets cast HP's would be the best choice. There are several mold makers that make heavier 35 molds that could work. I also assume you are planning to hunt with it? Deer? Hogs? If hunting deer then yes an expanding bullet might be better, but if hogs I prefer large flatpoints with a sharp edged flatpoint.

[Longranger44]

I understand the unique thing, I am running a G20 with a 6.6" barrel chambered in 45 Gap and to top it off I run 250gr and 300gr bullets and it is accurate and suppresses very well.
But back to the issue at hand, there are companies like Maker bullets and others that make solid copper subsonic bullets in 35 caliber but being you are looking to use a Glock platform you will be limited to what COL the magazine will allow and feed without issue. If you are looking for expanding bullets cast HP's would be the best choice. There are several mold makers that make heavier 35 molds that could work. I also assume you are planning to hunt with it? Deer? Hogs? If hunting deer then yes an expanding bullet might be better, but if hogs I prefer large flatpoints with a sharp edged flatpoint.

Interesting yeah I'll look into maker, I'm planning on getting some of their 280gr 350 legend bullets but hadn't even thought of them for this. I might hunt deer with it but I'd probably just get a 10mm barrel if I was going to do that. I'd love to hunt hogs but I'm up north and when I visit family in FL and TX Ive never been able to find private land and those pay ranches just aren't my thing. I always bring a gun with me though just in case lol. Sounds like cast would be a good way to go I'll have to look at moulds.

Very cool 45 gap, yeah I like that kind of stuff that pushes the boundaries and that very few others have. I can't begin to explain how little appeal putting together yet another glock 19 has to me. I have my carry guns that I leave mostly plain jane as they're serious tools but something like this I want to be unique. I want it to be something that my kids will find when I die and think, "what the hell was wrong with him?"

[shooting on a shoestring]

Hey Long…
I classify them as tools and toys.
My tools are serious, I take them serious, they work, they’re very practical.
My toys are FUN! I play with them. I spend money on them. They make me happy.
Happy is way funner than practical.

[JohnForrest]

For fun look at the 338 Razerback @ RMW xtreme. 338 bullet and a 10mm case. They did it to get 100 density loads.

They built me a 357 Sig AR barrel and I love it but admit as soon as it was done I think about it being a 9x25.

[475AR]

For fun look at the 338 Razerback @ RMW xtreme. 338 bullet and a 10mm case. They did it to get 100 density loads.

They built me a 357 Sig AR barrel and I love it but admit as soon as it was done I think about it being a 9x25.

Yes, RMW XTREME does alot of fun stuff. I have the 338 Razorback and with the 250gr bullets is scary quiet and accurate.
Ron also does the 9x25 Dillon and I have shot one he did with 88gr bullets and man that thing screams and is fun to shoot.

[RJM52]

I'm really split between doing the dillon build or doing a 357 sig build on the frame I already have. Everything about the 357 would be cheaper and more practical, but would a 10mm gun converted to 9x25 dillon really beat itself up any more than it would shooting 10mm?

You're correct...I was thinking the 9x25 on the small frame...which of course one can not do...

Having a G40 and G35, both fitted with .357 SIG barrels, they are both excellent shooters...just comes down to which frame fits your hand better.

[RJM52]

Two barrels? I don't trust the reliability of a 9mm in a slide designed for a 10mm case head if that's what you mean

I've got a 19 frame with a 23 slide and the 35 both in .40/.357/9mm... More 9mm has been shot though the gun than the other two calibers combined and zero feeding, extraction or ejection issues. My multi-caliber 1911s are the same...zero issues.

[justindad]

I’d love to have a 9x25 in a Sig X-Ten. No reason other than having fun.

[Longranger44]

You're correct...I was thinking the 9x25 on the small frame...which of course one can not do...

Having a G40 and G35, both fitted with .357 SIG barrels, they are both excellent shooters...just comes down to which frame fits your hand better.

Well I'm looking at the large frame p80 as they feel better in my hand than Glocks... But maybe it'd still be less comfortable than the 19 sized p80 frame. I'm really torn at this point because the 357 sig is much more practical and cheaper in every way...

357 sig > 9x25 Pros:
-cheaper parts to the tune of around $350 difference
-cheaper and locally available factory ammo
-much cheaper dies
-safe, published subsonic load data
-can use booster I already have (1/2x28 threading instead of a larger thread size for 9x25)
9x25 Pros:
-Powaa! Unlimited powaaaa!

[Longranger44]

I’d love to have a 9x25 in a Sig X-Ten. No reason other than having fun.

That's the only reason that matters

[Longranger44]

I've got a 19 frame with a 23 slide and the 35 both in .40/.357/9mm... More 9mm has been shot though the gun than the other two calibers combined and zero feeding, extraction or ejection issues. My multi-caliber 1911s are the same...zero issues.

That's what I've heard it seems like they usually work just fine for most people. I don't really care about shooting 9mm though because I've already got a 92a1 as my primary suppressor host and don't really need another gun for that purpose, just thought it'd be kind of cool to be able to suppress a 9x25 since everyone says how loud they are and then if I could also shoot some heavier subs though it that'd just be the cherry on top not really practical just something to tinker with that no one has ever done before

[gnappi]

Seems kinda pointless to neuter a 9x25 when subsonic 9x19 is easy and plentiful...But who am I to dissuade you from your project.

Agreed, maybe the OP has a pistol with a threaded barrel and silencer he wants to use and no other gun?

Anyway, it seems like a waste of 10mm brass and case forming effort.

[Longranger44]

Agreed, maybe the OP has a pistol with a threaded barrel and silencer he wants to use and no other gun?

Anyway, it seems like a waste of 10mm brass and case forming effort.

9mm can't shoot a 124gr bullet at 1700 fps

[reddog81]

.38 Special has a case capacity of 23.4 gr H2O and 9x25 has a case capacity of 22.8 gr according to Wikipedia. 9x25 has a max pressure double that of .38 Special. I would assume any reasonable .38 Special load would be safe in a 9x25 case.

[Longranger44]

.38 Special has a case capacity of 23.4 gr H2O and 9x25 has a case capacity of 22.8 gr according to Wikipedia. 9x25 has a max pressure double that of .38 Special. I would assume any reasonable .38 Special load would be safe in a 9x25 case.

Oh yeah I didn't realize 38 special was so close in capacity. Should be easy enough to find 165 or even 180gr data for the 38

[JohnForrest]

p80 kit on sale a MAS $109