Odd ZM LR 300

Caesidious · November 28, 2021, 03:25 PM

I have had a ZM LR 300 for about 10 years. Love shooting it. Took it in to possibly make some upgrades and the gunsmith thought it might be a one off or production? sample? Anyone know more about these?

bfoosh006 · December 1, 2021, 10:50 PM

https://en.wikipedia.org/wiki/LR-300

https://modernfirearms.net/en/assaul...ns-lr-300-eng/

https://www.google.com/search?q=ZM+L...client=gws-wiz

Caesidious · December 3, 2021, 04:34 AM

Thanks, I have read everything I can Google on them. That first article was the first one that showed the styles and years they were made. So that was a good one. Hopefully someone on here is more intimate with them.

stagpanther · December 3, 2021, 07:44 AM

Fascinating weapon--I'm a "student" of AR designs and never knew about this one. Interesting they call it direct impingement and it still uses an op-rod, to me it looks like splitting hairs between calling it a piston gun and direct impingement--which I consider to be any gas system with a fixed, non-moving gas tube between the barrel gas port and carrier gas key. I've long wondered if it would be possible to shorten the carrier to achieve a buffer-less conventional-sized upper using a piston and this seems to be an answer to that.

I'm curious about actual use experience compared to a "plain Jane" AR, if you don't mind my asking. Does the carrier need any special arrangement to remain "on track" inside the upper? Does it seem to hit any harder--or less--in terms of felt recoil? Does it have a system for adjusting gas pressure to the op-rod?

Caesidious · December 4, 2021, 02:48 AM

Let me start with answering the first question. The gas rod does move. Think closer to an AK. Now move the spring to the front.

To answer the next question, again it isn't straight forward, yes and no. It is the same but different due to the bobbed bolt carrier. I do not know if the gas can be adjusted, I have no manual for it so... Lastly feel. It feels heavier than a standard 16.5 inch AR. Front heavy. Sure it only weighs 6.5 lbs but it feels more like an M16A2 with a 20 in. barrel as far as front end weight. It has more of a slap when it shoots. I feel the recoil is less than a buffer tube. There is less muzzle climb. If I were to choose I would pick the ZM over a Plain Jane hands down. I would choose it over some of the lighter, race style guns with the skeletonized handgrips. CONS. Parts, it will be hard to get some parts for this, BCG would need to be machined. a lot of stock drop in parts don't work. Lasers, and other forward top mount items are tricky due to the gas block system. Now, I would likely trade for a SIG 516 or a MR556A1...
I will work on getting some pictures of her private parts when I get a chance to show the BCG and gas rod.

stagpanther · December 4, 2021, 03:32 AM

Thanks for the answers--front heavy might not be a bad thing if it helps to stay on target. The carrier--does it bang into any kind of spring at the rear of the upper? I watched the video of the disassembly and could't tell what activates the return of the carrier to pick up the next cartridge.

December 3, 2021, 07:44 AM	#4
stagpanther Senior Member Join Date: March 2, 2014 Posts: 12,927	Fascinating weapon--I'm a "student" of AR designs and never knew about this one. Interesting they call it direct impingement and it still uses an op-rod, to me it looks like splitting hairs between calling it a piston gun and direct impingement--which I consider to be any gas system with a fixed, non-moving gas tube between the barrel gas port and carrier gas key. I've long wondered if it would be possible to shorten the carrier to achieve a buffer-less conventional-sized upper using a piston and this seems to be an answer to that. I'm curious about actual use experience compared to a "plain Jane" AR, if you don't mind my asking. Does the carrier need any special arrangement to remain "on track" inside the upper? Does it seem to hit any harder--or less--in terms of felt recoil? Does it have a system for adjusting gas pressure to the op-rod? __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!*

December 4, 2021, 03:32 AM	#6
stagpanther Senior Member Join Date: March 2, 2014 Posts: 12,927	Thanks for the answers--front heavy might not be a bad thing if it helps to stay on target. The carrier--does it bang into any kind of spring at the rear of the upper? I watched the video of the disassembly and could't tell what activates the return of the carrier to pick up the next cartridge. __________________ "Everyone speaks gun."--Robert O'Neill *I am NOT an expert--I do not have any formal experience or certification in firearms use or testing; use any information I post at your own risk!*

December 1, 2021, 10:50 PM	#2
bfoosh006 Senior Member Join Date: February 17, 2009 Posts: 1,100	https://en.wikipedia.org/wiki/LR-300 https://modernfirearms.net/en/assaul...ns-lr-300-eng/ https://www.google.com/search?q=ZM+L...client=gws-wiz

December 3, 2021, 04:34 AM	#3
Caesidious Junior Member Join Date: November 27, 2021 Posts: 3	Thanks, I have read everything I can Google on them. That first article was the first one that showed the styles and years they were made. So that was a good one. Hopefully someone on here is more intimate with them.

December 4, 2021, 02:48 AM	#5
Caesidious Junior Member Join Date: November 27, 2021 Posts: 3	Let me start with answering the first question. The gas rod does move. Think closer to an AK. Now move the spring to the front. To answer the next question, again it isn't straight forward, yes and no. It is the same but different due to the bobbed bolt carrier. I do not know if the gas can be adjusted, I have no manual for it so... Lastly feel. It feels heavier than a standard 16.5 inch AR. Front heavy. Sure it only weighs 6.5 lbs but it feels more like an M16A2 with a 20 in. barrel as far as front end weight. It has more of a slap when it shoots. I feel the recoil is less than a buffer tube. There is less muzzle climb. If I were to choose I would pick the ZM over a Plain Jane hands down. I would choose it over some of the lighter, race style guns with the skeletonized handgrips. CONS. Parts, it will be hard to get some parts for this, BCG would need to be machined. a lot of stock drop in parts don't work. Lasers, and other forward top mount items are tricky due to the gas block system. Now, I would likely trade for a SIG 516 or a MR556A1... I will work on getting some pictures of her private parts when I get a chance to show the BCG and gas rod.