I have a Glock 27 Subcompact pistol in .40 caliber.

I've been practicing using Winchester White Box 165 grain FMJ, which has a truncated bullet shape similar to a semi-wadcutter. It is a fairly light shooting round.

My carry ammo has been Winchester PDX1 Defender, which is a 165 grain bonded jacketed hollow point. It feels like a much hotter round, with a louder report and more recoil than the Winchester White Box.

My local gun dealer does not carry this ammo, and he suggested that I try the Federal Guard Dog ammo which is 135 grain.

I've read up on this ammo and the idea is this: The full jacket encases a blue soft plastic ball. The inside of the jacket is scored, and the ball is backed by a lead bullet. On impact the lead bullet crushes the soft plastic ball which causes the jacket to expand and split open along the score marks. The photos I've seen show almost uniform expansion.

All these brands of ammo feed reliably in my Glock. But the Guard Dog feels significantly lighter in recoil than the Defender ammo and slightly lighter in recoil than the Winchester White Box. This is probably because of the lighter bullet weight (135 gr. vs 165 gr.)

Does anyone know if the short barrel length on the G27 is going to allow sufficient velocity to cause this expansion?

Does anyone have an informed opinion on this ammo.

What makes this perplexing for me is that I shoot the Guard Dog ammo better and more accurately that any of the other types I've tried.

I'm not sure what the barrel length is on your Glock but...

I have chronographed identical 180 grain ammunition through my Ruger P-944 (4.2 inch barrel) and my S&W 4013TSW (3.5" barrel). The Ruger averaged 1072 fps, the S&W 1003 fps. 70 fps probably won't make that much of a difference in my case.

Never shot any but I have inspected the rounds before and after expansion. They seem to always expand and do so uniformaly.

They look the same as Federal EFMJ (expanding fmj).

My only concern would be the Point of Impact, the 135 grain ammo may hit significantly lower than your heavier bullets. I'd love to carry the Cor-Bon ammo in my EAA Witness, but it was made in 1990, and the sights are regulated for the early 180-grain ammo. YMMV.

That is exactly what the Guard Dog ammo is, just with some new marketing hype. That being said it is the most accurate 45 ammo out of my Sig P250 compact. So that is what I carry, now my SA 1911 UC my carry ammo is the 185 gr Hornady XTP. I haven't shot any of the Guard Dog out of my 9mm or 40 yet. Current carry loads are the 180 gr Winchester bonded in the 40 and 115gr +p Speer GD in 9mm.

Guard Dog is good for communist states that prohibit hollow point ammo. For me, I prefer a Speer Gold Dot over most any other round.

Am I the only one that see's this as the same idea as the Hornady Critical Defense bullets? They both use some kind of soft polymer to just about promise expansion but the Fed bullets have some kind of extremely thin jacket coating. My guess is the Fed bullets need just a bit more velocity to make the jacket smash the polymer than the Hornady bullets require for the polymer to push the walls to expand.

Troutoutdoors9 has a series of videos on ballistics that are fairly convincing to me that the Guard Dog is pretty much at the bottom of the heap when it comes to defensive rounds.

See: tnoutdoors9's Channel - YouTube

The Guard Dog no only lacked sufficient penetration its expanded petals are rounded and do less tearing than a conventional round would.

I will be going back to my earlier defensive round, the Winchester Defender.

Thanks for the replies.

Packard

Detroit PD has been carrying the Federal EFMJ for years and has had good results. The Guard Dog line is just new marketing for the old round. There are some locales that prohibit JHPs for civilian carry, including New Jersey, and the Guard Dog/EFMJ round is an acceptable and capable round.

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The Guard Dog test tnoutdoors9 did was with 9mm and I have seen .40 tests that show greater than 12" penetration and great performance. I personally would not use the 9mm Guard Dog after seeing his test but I regularly carry .40 Guard Dog. This video by ScubaOz is pretty good. https://www.youtube.com/watch?v=X47YlJANRAk