My SWAT team asked me to look into a multi-shot launcher.
Why did Penn/CTS develop the pump-action? Were there problems with the spring-advanced mechanism? Is it faster to pump? The models I'm considering are the P540-3 and L640-3 (both 6-shot with M4 stock).

I'm assuming a Milkor M32A1 will not operate with most less lethal munitions, since it's gas operated. Anyone have experience there? I emailed them anyway for pricing. 

Milkor makes. LLl version that works with all 40mm LL rounds out there    Expensive, but the best on the market.  Safariland has a new multishot that appears to be good to go.    I've only shot the Penn/CTS once it had some issues that I don't quite remember , only dry fired the pump version

What rounds are you using ?

http://milkor.com/milkor-3738-40mm-mar/
Is this it? MAR - Multiple Anti Riot

The Safariliand/LMT multi only holds 4 rounds http://www.safariland.com/products/less-lethal/launchers-and-accessories/launchers/40mm-tactical-4-shot-launcher-1183287.html and I'm not sure what Safariland means when they state it's "not designed to fire 40mm high velocity HE ammunition". Are they referring to MK19 40x53mm HV rounds, or do they mean it cannot handle LV military 40x46mm?

The only stuff we have left from the last time any were purchased are some direct-impact reloadable rounds. We'd like to get some CS and OC projectiles.

The safariland is only rated for Lv LL rounds  In theory, you could fire LV explosive rounds - it's not made/warranted and don't know how many you could get down the tube before "issues

I guess VLtor is no longer Milkor USA - that is not what I was referring to   VLtor makes a LL version of the Mil MGL , not that 70's era looking launcher from SA

Found it: http://www.milkorusa.com/product/mgl-ltl/
https://www.vltor.com/shop/mille/vltor-ltl/

I'm not sure I want a launcher that can't handle 40x46mm LV all day every day. That's no extraordinary feat.
Being able to cycle all the LL stuff reliably sure is though. Looks like the LTL is spring-advanced.

I guess Abrams Airborne Manufacturing is Milkor USA and VLTOR Weapon Systems.
http://www.abrams.com/contact.html

PENN rotaries suck.  You have to pump them just right each time to make it rotate correctly.  Have seen just about everyone have a fail to fire as a result at least once.

Old DefTec spring wound rotaries also had issues.

Older Penn 37mm's I have not fired as much.  Just know the current pump rotaries are hated enough that we all carry single shot DefTecs and the newer LMT's from DefTec.  Those are bullet proof.  The LMT single shot launcher is light and works great-buy those instead of a rotary.  People hate rotaries due to the weight, so we won't even look at spending the money one the new 4 shot at this point.

Good to know. Thanks!

It seems to me a 4 shot rotary is the worst compromise. I think we'd be best served with the 6 shot Milkor USA LTL, but that's up to the lieutenant now. We have 2 Penn single shot 37mm launchers currently. They'll be sold if we switch to 40mm (which I recommended).

I never received an answer as to why the Penn Arms pump was developed, but I suspect it's for ease of reloading. I think I'd rather wind.

Milkor mentions selecting an individual chamber, but that seems like a bad plan under stress. I'd rather fill all 6 with whatever is selected at the time.

Milkor offers a steel barrel upgrade for an extra $75. They told me the aluminum LTL barrel is good for about 5,000 rounds, depending on the driving bands utilized, and that M203 barrels are only good for around 3,000 rounds in military use. They don't think cops can wear out a steel barrel with less lethals.

I'd like to supplement the rotary with one or two underbarrel M203's but I doubt that'll happen. lol
If anyone's seen an agency do that, please name them.

Alternatively, I'm considering tracking down some old LESO M79's and seeing if anyone wants to transfer a couple to us. 

If you find more than you need pass the info my way.

My agency has 2 Penn Arms rotary 40mm launchers.  I believe the rotary action is so that you can "select" your round.  The trigger is double action so you can pull to your hearts content, and the cylinder rotates with the pump action separately.

I'm not impressed with them.   I've begged to trade them on something useful like a doorstop or a used couch.