17 replies to this topic

[The1930sRust]

Several weeks ago I was fortunate enough to obtain a 1921 actuator assembly. It consisted of the actuator, pilot, and two each buffer tubes and springs, and some extra buffer disks.



As far as I can tell, it is totally unmarked. I had been tinkering with the idea of having a standard 1928 actuator modified to the specifications of the 1921, in order to speed up my 1928 just a tad. PK suggested the modification, and even sent me an image of such a beast.



Having come across the real McCoy negated that option. I did, however, purchase one of PK's hybrid 1921-1928 buffer assemblies. I was worried about the purported design flaw of the 1921 actuator (lots of metal on metal contact), and the possibility of it damaging the softer metal of the West Hurley receiver.



PK's hybrid buffer, utilizing a special buffer disk, itself is a piece of work, and was a perfect fit of course. I got a chance to get to the range today and try it all out.



I ran nearly 300 rounds though it all, without a hitch. Although I have not been able to quantify the speed of the new actuator, it is definitely faster. It just sounds cooler! The overall action seemed smoother, too.

Here is a short 3 MEG .MOV file of the gun running through 50 rounds.

1921 actuator video

[full auto 45]

Great video work Chris. Looks like the actuator is slipping but moving to fast for the camera. Good work.

[LIONHART]

Nice video of your Chopper Chris!

[First Sergeant]

Chris,

Great pics but I can't get the video to open.....any suggestions?

Chuck

[ausrotten]

i think you need quick time. well, thats what mine loads it up in.

[PK.]

Minor correction; the buffer disk shown in Chris’ post and noted as an SRT part is actually of my own manufacture. They are different but similar and the mistake is certainly understandable.

[The1930sRust]

Yeah, sorry 'bout that. I thought you said that was what you used. Or maybe I recall you mentioning them as replacements for the 21 buffers. There goes my brain again....

Yes, the video requires the www.apple.com free Quicktime viewer.

[Zamm]

Chris,
Weeeeeeeeeeeaaaaaaaaahhh !!!!! Gad that thing is fast!!
Amazing view! Your an artiste!
Zamm

[ausrotten]

thats a very clear video! nice work mate.

[PK.]

We did discuss SRT Chris, they are the only ones I know of who make replacement disks for the ‘21 buffers (the little red ones as shown in your photo, except I think theirs are gold color as the 28 disk show is). So you are not loosing it as badly as you might think!

[Norm]

I love the video! The Tommy-Cam!

What size drum was that you emptied? A 100 or 50?

Norm

[Johnny.45]

Chris,

That looks like a great setup. The 21 actuator and PK's Mod 21/28 buffer pilot is a great addition to your 28 WH. I'm trying to collect as many spare 28 parts as I can, and now I'm going to look for those 21 parts that PK is manufacturing.
Thanks for sharing the information on the 21 parts kit.

Outstanding,
Johnny

[The1930sRust]

Norm:

That is a 50 round L drum. No C's yet! Couldn't possibly afford to feed one now....

Johnny:

PK's actuator made to '21 specification/hybrid buffer system is the way to go for pepping up a 28 for sure. I think if you supply the 28 actuator, he'll do the rest...

I also did some quantitative analysis (always wanted to say that) of the videos, and it empies a drum in 3.01 seconds (give or take). Eyeballing it, that is around 900 RPM.

Also, there is an unusual "lunge" (or perhaps it is a "lurch) as the last round plays out. I don't recall feeling this with the 1928 actuator.

Zamm and everyone else, glad you liked the flick!

[full auto 45]

That's pretty good. I clocked my "L" drum at 3.83 sec. or about 785 rpm. Amazing what you can come up with on a video and some editing software.

[PK.]

With all due respect, I must take exception to the term “Speed Actuator”, it is much to reminiscent of the terms used to sell dangerously lightened parts by others in the past.

Lets be clear; the actuator shown in the photo I sent Chris and displayed at the beginning of this post is a 1928 Actuator that has been machined into a “by the print” ’21 style. It is for all intents and purposes identical dimensionally to an Actuator as supplied by Colt for the 1921 gun. No magic, no mirrors. Installed with a 21 recoil spring and either an original 21 buffer system or a hybrid buffer system, the function is as originally designed for the 1921 gun.

[Walter63a]

Chris, that's great video work. Thanks for sharing. Regards, Walter

[The1930sRust]

Paul:

Boy! I've just screwed this post up from top to bottom! Thanks for keeping me in line. OK, I actually used the phrase "deleted term actuator" to draw attention to the old "speed bolts" to suggest this is the right way to speed up a 1928. I may even add a section in the FAQ about this, as the speed bolts are listed there I think. Anyway, next time I'll use a more appropriate term. How about "modified actuator/hybrid buffer system"? MAHBS?

[First Sergeant]

Got the video to work, thanks for the download info.

Good shooting there Tex (Chris) looked and sounded great. Thanks for a trip to the range but without the cleaning.

Chuck