+P in newer vs. older S&W Airweights.

In The Ten Ring · March 19, 2018, 07:16 AM

Why are the newer Airweights such as the S&W 438 and 638 +P rated while the older Model 38's aren't?

What has been done to the aluminum frames to allow this?

T. O'Heir · March 19, 2018, 01:03 PM

There was no SAAMI standard for what '+P' means until relatively recently. The "P" in +P meaning pressure.
However, it's not terribly difficult to beef up the alloy of Al. Al is used for light tank and AFV armour now.

Slamfire · March 19, 2018, 02:17 PM

Only S&W can answer if the non +P revolvers are safe with +P loads, and they might not be. All depends on the steel alloys and the heat treatments.

As for the later Airweights, do understand, a continuous diet of +P will accelerate wear on an Airweight. I don't know the limits, but you can expect the timing to be affected, maybe the extractor star to get loose, maybe the hand to batter. No firearm is built to last forever, and these lightweight pistols are designed to be carried a lot, but shot a little. If you want the maximum lifetime out of an Airweight, for practice, shoot standard pressure loads, and load up the +P for self defense.

Nick_C_S · March 19, 2018, 02:37 PM

Quote:

Only S&W can answer if the non +P revolvers are safe with +P loads

I agree. I have a Model 60 (steel J-frame snubby) I purchased new in 1984. Just a few years ago, I called S&W and asked them specifically about +P ammo. The answer was basically "all of our steel J-frames can safely shoot +P ammo." In 1984, "+P" didn't have a specific definition; otherwise, my gun probably would have been stamped as such on the barrel.

Just speaking for myself, with alloy frames, I'd shoot +P's only occasionally - even if Smith deemed it safe.

JERRYS. · March 19, 2018, 03:46 PM

whats already been said above.

next, I find that +p generally doesn't offer me better performance (in back yard water jug tests) but it does offer me slower follow up shots. when I rip off a cylinder full as fast as I can with standard and +p I find that my +p groups are noticeably larger at 7 yards. in other words, (for me) to shoot as good a group with +p as I do standard pressure I have to shoot a little slower.

is that a good trade off for you? I do not have a ported airweight. I do have a ported 640 no dash .357 and it makes a huge difference in speed shooting.

bn12gg · March 19, 2018, 04:40 PM

For putting holes in paper plates with my SW 37 or Cobra I prefer wadcutters.

.02

David.

straightshooterjake · March 19, 2018, 08:15 PM

The modern +P rated airweight J-frames are quite tough. I shoot them quite a bit, and they do not loosen up or go out of time easily. I have over 3,000 rounds through one of them, and it has not had any problems. I shoot mostly standard pressure rounds, but I do shoot +P when I feel like it, and it does not cause any issues.

The older airweight guns are a different story. They have a reputation for cracking the frames right under where the barrel screws in. I would only shoot one with standard pressure ammo, and probably pretty sparingly. I would not shoot one on a very frequent basis like I do with a modern 642.

March 19, 2018, 07:16 AM	#1
In The Ten Ring Senior Member Join Date: January 26, 2018 Posts: 380	+P in newer vs. older S&W Airweights. Why are the newer Airweights such as the S&W 438 and 638 +P rated while the older Model 38's aren't? What has been done to the aluminum frames to allow this?

March 19, 2018, 01:03 PM	#2
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	There was no SAAMI standard for what '+P' means until relatively recently. The "P" in +P meaning pressure. However, it's not terribly difficult to beef up the alloy of Al. Al is used for light tank and AFV armour now. __________________ Spelling and grammar count!

March 19, 2018, 02:17 PM	#3
Slamfire Senior Member Join Date: May 27, 2007 Posts: 5,261	Only S&W can answer if the non +P revolvers are safe with +P loads, and they might not be. All depends on the steel alloys and the heat treatments. As for the later Airweights, do understand, a continuous diet of +P will accelerate wear on an Airweight. I don't know the limits, but you can expect the timing to be affected, maybe the extractor star to get loose, maybe the hand to batter. No firearm is built to last forever, and these lightweight pistols are designed to be carried a lot, but shot a little. If you want the maximum lifetime out of an Airweight, for practice, shoot standard pressure loads, and load up the +P for self defense. __________________ If I'm not shooting, I'm reloading.

March 19, 2018, 08:15 PM	#7
straightshooterjake Senior Member Join Date: September 7, 2016 Posts: 122	The modern +P rated airweight J-frames are quite tough. I shoot them quite a bit, and they do not loosen up or go out of time easily. I have over 3,000 rounds through one of them, and it has not had any problems. I shoot mostly standard pressure rounds, but I do shoot +P when I feel like it, and it does not cause any issues. The older airweight guns are a different story. They have a reputation for cracking the frames right under where the barrel screws in. I would only shoot one with standard pressure ammo, and probably pretty sparingly. I would not shoot one on a very frequent basis like I do with a modern 642. __________________ My blog: http://straightshooterjake.blogspot.com/

March 19, 2018, 03:46 PM	#5
JERRYS. Senior Member Join Date: September 23, 2013 Location: Alabama Posts: 2,969	whats already been said above. next, I find that +p generally doesn't offer me better performance (in back yard water jug tests) but it does offer me slower follow up shots. when I rip off a cylinder full as fast as I can with standard and +p I find that my +p groups are noticeably larger at 7 yards. in other words, (for me) to shoot as good a group with +p as I do standard pressure I have to shoot a little slower. is that a good trade off for you? I do not have a ported airweight. I do have a ported 640 no dash .357 and it makes a huge difference in speed shooting.

March 19, 2018, 04:40 PM	#6
bn12gg Senior Member Join Date: February 19, 2011 Location: Winter Park, Florida Posts: 470	For putting holes in paper plates with my SW 37 or Cobra I prefer wadcutters. .02 David.