[SunshineJerry]

I just did one. I thought there was a video. If there is, I couldn't find it. I couldn't even find a video on now to disassemble it further than a basic takedown for cleaning. Being handy and having installed one in 3 PMR-30's, I felt confident I could do it.

Here's my feedback:

Short Version: I was able to do it. The CMR has a lot of similarities to the PMR -- and some differences.

Recommendation to Others: If you're handy, have tools, and have done this on a PMR, or if you're experienced at gunsmithing, go for it. Otherwise, I wouldn't recommend it. Some adventurous folks might go for it, anyway, and I wish them success.

Major Difference from PMR: The biggest difference with the CMR is having to file the barrel trunnion. It's tricky, and there's not much to go on besides this pic. How much do you file? First, hold up both feed ramps to it, and you'll see why it needs filing for the Mcarbo upgrade. It seems to function like an extension of the feed ramp. So, I made sure everything was clear when I put the Mcarbo ramp up to it. Then, for good measure, I beveled all my edges slightly. When I finished filing, there were a lot of metal filing chips on the barrel assembly. A few squirts of air from the compressor, and they're gone. If you don't have a compressor, you could brush it, then clean it with wipes and CLP.

Minor Differences from PMR: The screw pattern is a little different. The slide lock doesn't have as much play, making it harder to connect the spring on the feed loader to it. After struggling way too long with the Mcarbo tool, I was able to do it in seconds using a piece of soft, flexible, multifilament fishing line. This technique would work on the PMR, too.

Othe PMR Upgrades: I did the mag release. It was identical to the PMR. I didn't bother with the trigger upgrade, but it looked the same. There is no recoil spring upgrade.

No Live Test Yet: I was hoping to go the range this week, but it looks like it'll be next week before I get to go. I'll update after I go.

 

[Jimbro]

@SunshineJerry... Thanks for your work, you lead the way. Been dying to try this on my CMR. Why don't you make a video?

 

[SunshineJerry]

Why don't you make a video?

I'm not set up for making vids. Maybe this post will inspire somebody.

Chris from Mcarbo makes great ones, and he loves feedback and suggestions from users. Not only is he the head research guy, he's also the owner. I didn't realize that at first, he was so real, unpretentious, and easy to deal with.

 

[Jimbro]

Been doing MCARBO upgrades for a couple of years. Do love his videos, they make it so easy. They got me into working on firearms.
I emailed him to make a video of the CMR 30 feed ramp modification, but no response as yet. So far, you're the only one I can find who's done it.

 

[CMR30Operator]

Check my post history. I have mine in, but last range trip was a bust to try the mod out... Same as Jerry here unable to test as of yet.

I'll post back as soon as I have a trip in and have shot it. Did the mag release as well. Hoping for good results.

 

[Jimbro]

Yes, the mag release should be exactly like the PMR 30. Thanks, I'll be watching for your post.

 

[jaboomgaarden]

Check my post history. I have mine in, but last range trip was a bust to try the mod out... Same as Jerry here unable to test as of yet.

I'll post back as soon as I have a trip in and have shot it. Did the mag release as well. Hoping for good results.

Still think that range guy had something up the keister. (No offense, if he's related)

^^^ you can't take offense, because I said "no offense". Those are the rules

 

[SunshineJerry]

Went to the range today and went through about 10 mags. Everything fired great, with two glaring exceptions.

Browning BPR ammo had failure to feed issues with both the CMR and the PMR. They're 40 grain, 1910 velocity, and copper jacketed, so, they have the right specs. They just didn't work. Same with the Hornady Critical Defense 45 grain FTX.

Winchester Super X, with identical specs to the Brownings, and Armscor 40 gr jacketed hollow points, all sailed without a hitch.

Also, in an Mcarbo video, Chris put 31 rounds into his PMR and fired them all. I tried it in 2 mags, and couldn't get the first round to chamber on either. 30 is enough.

 

[Jimbro]

Good to hear the new feed ramp is working. Have heard about problems with Browning BPR. Shame about Hornady Critical Defense. Was it the same with the PMR-30? It has great terminal ballistics based on Lucky Gunner for penetration and expansion. Only Speer GDHP bested it.

 

[SunshineJerry]

Shame about Hornady Critical Defense. Was it the same with the PMR-30?

It was consistent. Everything that worked in PMR's worked in CMR, and the two that jammed did it in all 3 of my PMR's and my CMR.

So, I know this flavor of guns doesn't like those kinds of ammo, even with the Mcarbo upgrades. It's not any particular gun.

I only had a few Hornady's, so they're gone. I have a bunch of the Brownings, because it was the only thing I could find at a reasonable price the day I ordered them. I'll use them at the range, and they'll force me to practice my tap rack bang routine, which I hope I never need to use it in a real situation.

I forgot to mention CCI Maxi Mags. Those worked perfectly, my last time at the range, before the Mcarbo upgrades, but I only have a few of them left, and I'm saving those until I get more.

 

[CMR30Operator]

...
I forgot to mention CCI Maxi Mags. Those worked perfectly, my last time at the range, before the Mcarbo upgrades, but I only have a few of them left, and I'm saving those until I get more.

So you are not reporting any realized function improvement? Or am I missing some history on your last range visit?

Interesting that you had issues with the Hornady as that was one of my better performers...

Federal 50 the best.

CCI game point worked till I got north of 200 rounds last trip.

Just recently got a case of the Maxi Mags been waiting to try those out.

Good news on the Armscore, I hope that improves for me I have over 500 I have been sitting on.

 

[SunshineJerry]

So you are not reporting any realized function improvement? Or am I missing some history on your last range visit?

Didn't haven any problems prior. The guns are all new. I just read about the problems others have had with them, didn't want to have them, so I did the upgrades.

In the video by Chris at Mcarbo, he was able to run full mags of anything through them after the upgrade. I wasn't, but some ammo did run flawlessly.

Hoping to go back for more target practice, but the first thing I'll do there is use up the 1000 Brownings. Maybe after things break in, they'll do fine, too. If not, I'll get some random tap, rack, bang practice.

Maxi mags in 40 gr hollow point are hard to find. I found them for over $.40 each with shipping, but there was a 2 box limit. Just ordered another 500 Armscor. They did well on gel tests, were more reasonable at $.29, and had no limits.

 

[CMR30Operator]

Was hoping to see improved function post install as I've been having feeding issues.

Still hopeful for my upgrade as I could see the plastic feed ramp deformed from rounds removing material...

Whew I had to think 2x before getting my TMJ Maxi Mag at .25 per. Only reason I swong was because I have yet to shoot THE round for the CMR and figured it may be a while before the price comes down. I wouldn't touch the JHP at .40 unless I it was for purpose. For instance I've no issues with the buck plus a round I pay for what I load up for cary in 9 but like wise not buying at todays rate of.50 for plinking. Lucky I tend to buy in bulk when there are deals and could probably last another 6 months of plinking ammo... But have already slowed my roll because the more I shoot the more I want more ammo in reservation XD

Anyhow looking to hit the range this weekend and will report back as well.

 

[SunshineJerry]

Was hoping to see improved function post install as I've been having feeding issues.

I didn't try any Brownings or Hornady's before the install, so I don't see anything got worse. I just didn't have the overwhelming success Chris had in his video. Nonetheless, there's no way the Mcarbo feed ramp is going to deform.

I also like the upgraded mag release. I can feel the difference, both in how it seats, and how hard it is to hit it by accident.

 

[jaboomgaarden]

Its crazy to me that kel tec would go with a plastic feed ramp. They have to know the amount of wear and tear that it goes through.

I think somebody mentioned this but they ought to make it a standard peice on them going forward.

Thank you MCarbo.

 

[jaboomgaarden]

I did the mcarbo feed ramp upgrade. It was pretty easy to follow Chris' video he put out on the PMR feed ramp installation. They are almost identical.

The two nubs that needed to filed down were easy to reach with a simple rat tail file I had in my tool box.

I realize I'm repeating what SunshineJerry reported, but I just wanted to let you know that another yahoo managed to knock this project out about an hour on his kitchen table while his wife was gone and cleaned up before she got back

The wife part is the most important peice of advice I can give. Don't let her find out you do gun projects on the kitchen table.

 

[CMR30Operator]

So range report from yesterday with the mag release and feed ramp upgrades from MCARBO.

Shot Federal 50, Hornaday 45, Armscore, CCI Gamepoint, and CCI Maxi Mag.

Starting with what did not go well.

Like Jerry I had issues with the Hornaday 6 mags gave 4 FTF one mag had two failures within a few shots.
The gun was only on it's third mag (and first with Hornaday) when failures did occur the round was crushed between the cuts of the hollow point. I believe these cuts (intentionally so) weaken the round and when things line up just right / variances give the cuts cause the head to deform and the failure to feed is introduced.

The Armscore I only shot after 300 or so rounds and at first gave failure to lock backs... also I forgot how dirty this ammo is XD... I did get one failure to feed out 100 though, otherwise it was a mix of worked great and failure to lock backs over 4 mags of 25. The failure to feed really mangled the round to the point I was glad it didn't go off out of battery.

The Maxi Mag I didn't start shooting after round 300 shot 4 mags of 25 of these as well. The very last mag had a failure to lock back after 500 rounds.

What went well: 60 rounds CCI Game point and 60 rounds of Federal 50 shot at the start and end of 300 rounds in and order I don't recall.

This is a phenomenal improvement in function in my CMR, from where it started off.

I have great confidence in Federal 50, and CCI Maxi Mag. I think CCI Gamepoint might be a good defensive load but would like to shoot a bit more than 60.

Only failure encountered in the first 300 rounds was with Hornaday, the only failures to feed where both rounds with week nose properties. This makes perfect sense really. The Hornaday is coper w/ machined cuts and the Armscore is exposed lead. I believe this allows the nose to deform causing the failure. Everything else just ran and only when the gun we pretty dirty did I get any failure to lock back.

Also per another users suggestion here (can't recall) I used Birchwood Casy Gun Scrubber to clean up after, and I am totally in love XD this stuff is amazing. It cleaned out thousands of rounds of debris from all over my CMR. I will suggest that you remove MAG PULL gear though In addition to the sites I have the angled grip and none of them liked the Scrubber much. The sight post started to oxidize almost instantly and it 'dried' up the polymer. Everything looks like new after some gun oil was rubbed into the polymer and reapplied to all the metal bits, but next time I'll just be removing it all. The lower and everything else had no issues. I was too lazy to remove the buffer at the end, but saved hitting that till the end, then sprayed it down with WD-40 TPFE lube right after.

Also used the scrubber to hose down my mags, then I followed up with the WD-40 TPFE dry lube. I had reported that I started to dent rounds start ~25 with the Maglula loader. Afterward, loading to 30 w/o any denting, and the loading just feels so much better. If you are denting rounds with the Maglula I recommend doing this. This may improve feeding as well, but can't really say.

 

[LESchwartz]

I've done the "5-second magazine fix" to all my mags, so I don't think I'll need to do the mag release. The feed lips are now holding up against the bolt rail and the rifle feeds reliably. Because of this, I haven't swapped out the feed ramp -- despite not a big fan of the plastic material for the feed ramp.

But I couldn't help wondering if the plastic feed ramp might provide for some "give" so that the Hornaday ammo wouldn't be crushed. It would have been nice to see how the rifle shoot after just doing the mag release.

Larry

 

[CMR30Operator]

I've done the "5-second magazine fix" to all my mags, so I don't think I'll need to do the mag release. The feed lips are now holding up against the bolt rail and the rifle feeds reliably. Because of this, I haven't swapped out the feed ramp -- despite not a big fan of the plastic material for the feed ramp.

But I couldn't help wondering if the plastic feed ramp might provide for some "give" so that the Hornaday ammo wouldn't be crushed. It would have been nice to see how the rifle shoot after just doing the mag release.

Larry

The Hornady behaved no worse or better then before the mods. I believe it was responsible for the damage on my plastic feed ramp before replacement.

 

[LESchwartz]

The Hornady behaved no worse or better then before the mods. I believe it was responsible for the damage on my plastic feed ramp before replacement.

I didn't catch that you feed ramp had been damaged.

Larry