PCC jam, why?

[gun'sRgood]

WAIT.

You didn't try/consider everything. And I would try the following before removing metal.

Have you considered using RMR JHP MPR NUKE (Multi Purpose Round for 9mm/.357 Sig ... and "NUKE" for expanding with 3 petals)? - https://www.rmrbullets.com/shop/bullets/pistol/9mm-355/9mm-115-gr-rmr-jhp-mpr-nuke/

Also comes in 124.gr - https://www.rmrbullets.com/shop/bullets/pistol/9mm-355/9mm-124-gr-rmr-jhp-mpr-nuke/

And RMR offers 5% THR discount.

Instead of typical truncated cone nose profile of many JHP, RMR MPR has rounded nose profile for more reliable feeding.

Give it a try (BTW, ELEY uses RMR bullets for their centerfire match ammunition so you are buying match grade bullets at bulk bullet pricing).

This combination should be able to fire just about anything I feed it. A lot of 9mm PCC companies are following a feed design that is from first gen. Glocks and the military using RN. A number of companies are upgrading this design because of the problem I listed. Seems I'm not alone. I do really appreciate your input. Thx.

 

[gun'sRgood]

No offense intended at all... but are you sure that is 115gr Hornady Critical defense ?

That bullet profile looks far less tapered then a 115gr CD bullet.

I ask, because very wide HP's ( in my case SIG V-Crowns ) don't feed well for me.

I would suggest polishing the cone around the barrels entrance, and possibly the bolt face ( helps the casehead smoothly slide across it ) .

View attachment 1109939

I'm quite sure. I'm having this barrel re-throated and plan of ordering the cheapest 9mm PCC barrel I can find. I only have X-Y axis on my lathe and no DRO. However, with the years of woodworking, I plan on trying to duplicate the barrel when it gets here. Thanks for your thoughts. Appreciations.

 

[gun'sRgood]

Oh Boy... if the round actually has to make a jump that poses a bigger problem. I cant tell from the photo if the cartridge has been fully release from the feedlips or if the magazine is still hanging on to the rim.

You can tilt the angle of the feed up a little. All kinds of tricks to adjusting magazines. If you have a magazine that works while others dont its a good investment to have a cheap protactor on hand to get a measurement of the feed angle on the working magazine then go from there.

I would definitly be working the magazine before I started grinding on feedramps. Always try the least expensive option first.

If that round actually has to make a JUMP into the chamber without bullet tip contact.....bolt speed forward is your friend.

What happens when you chamber a dummy round really slowly (ride the bolt)?

Really good thoughts and intelligently put. Sage advice. The mags are all original Glock but that doesn't mean anything if it's a problem with the mags. I will, or have started there. With RN's or smaller HP's [diameter] The gun runs flawlessly. And is more fun to shoot than ... well I can't tell you how much fun this build is paly with. Cost of parts was never an issue. And it looks as good as it shoots.... unless Critical defense, and I would suppose critical duty. It's Critical Duty that I want to keep in it for HD. Please keep in mind any further posts. I enjoy how your mind works.

 

[gun'sRgood]

This was my only complaint with my old Glock mag 9mm AR.
I still run Metalform mags with a Hahn magwell adaptor which has dual built in feed ramps. Even with a Rock River Arms barrel which had absolutetly no feed cone, it fed any truncated or hollow point bullet. It also has a very horizontal feed angle so the bullets sit as high as possible.
The Glock setup had a LONG jump from the mag to the chamber, and only fmj round nose loads worked 100%.
IMHO unless you can somehow get your rounds to feed higher, or recut that barrel with a more generous feed cone, you're either gonna take a chainsaw file or a grinder and round off that edge you're hitting on, or stick to fmj.

Yep! Great thoughts! I give you any award I might have. Thx.

 

[starling]

Really good thoughts and intelligently put. Sage advice. The mags are all original Glock but that doesn't mean anything if it's a problem with the mags. I will, or have started there. With RN's or smaller HP's [diameter] The gun runs flawlessly. And is more fun to shoot than ... well I can't tell you how much fun this build is paly with. Cost of parts was never an issue. And it looks as good as it shoots.... unless Critical defense, and I would suppose critical duty. It's Critical Duty that I want to keep in it for HD. Please keep in mind any further posts. I enjoy how your mind works.

Depending on the distance of the front of the feedlips and the contact the nose of the bullet tip makes it could just be that the 9mm pictured is to short overall in length. If you chamber a round really slowly you might be able to catch the feedlips releasing the case too early. Its pretty rare to run into this with pistols/rifles but I see it once in a while with certain pistols useing certain cartridges. Being that your PCC/PDW is a modified rifle (long cartridge) design to use Glock magazines it could be something to check for.

Just be careful cycling live rounds for testing the feed. Might be best to remove the fireing pin if you are not on the range and working on this in the house/shop. If you reload and can make some dummy rounds with that particular bullet..... do that.

Important thing is that it runs on RN FMJ. Thats most likely what the designers built it around.

Hard to diagnose this stuff without the firearm actually in my hands. Its not rocket science but there is a sequence of events that has to be followed for reliable feeding.

 

[bfoosh006]

FWIW... polishing the feed cone is super simple.

I use a shotgun bore mop attached to a spare piece of Hoppes cleaning rod ( with the shotgun adapter from a universal kit. ) spun via a cordless drill.

Some polishing compound added to the mop head and some kind of oil. The oversized mop shouldn't even come close to slipping into the 9MM chamber. so it will ride the feed cone surface.

And Glock mags tend to release the round prior to fully chambering.. so do lightly polish the bolt face as well.

Also the extractor "face" ... NOT the claw, just the portion that slips over the cartridge rim.

 

[Barbaroja]

Looks like xtp hollow point not there Ftx that they load in critical defense.

 

[gun'sRgood]

Looks like xtp hollow point not there Ftx that they load in critical defense.

Sorry, but I have no idea what you mean. Hornady Critical Defense does not run. Regardless of how clean and polished every part is. It runs RN w/o problems.

 

[LiveLife]

Hornady Critical Defense does not run. Regardless of how clean and polished every part is. It runs RN w/o problems.

I could send you a sample of RMR MPR which has RN profile with cut tip to see if they will feed in your PCC.

 

[Barbaroja]

Sorry, but I have no idea what you mean. Hornady Critical Defense does not run. Regardless of how clean and polished every part is. It runs RN w/o problems.

The bullet in the photo looks to be a XTP hollowpoint, not an FTX hollowpoint that is used in the critical defense load

 

[Riomouse911]

If the OP will show a pic of the nose of that particular cartridge shown in the gun, the CD/XTP debate will be settled.

You are on the right path. It looks like the feed ramp is a tiny bit too abrupt for those particular rounds so the HP meplat is jamming in straight. The FMJ bullet profile is riding up and over that spot.

Let us know how your experiment works out.

Stay safe.

 

[gun'sRgood]

I could send you a sample of RMR MPR which has RN profile with cut tip to see if they will feed in your PCC.

That is incredibly kind of you! Thanks. Very meaningful. I am in contact with a company who will mill the feed ramp. Then I thought, It's never just one gun who has the one problem. There's always several folks who all have the same issue. Kind of why forums like this exist. So before I send it in to be milled, I've contacted Ranier to see what they say. I really like this company and the president used to be a friend. Time and distance issues. A pic of the rounds is coming. Thanks again for the kind offer.

 

[gun'sRgood]

If the OP will show a pic of the nose of that particular cartridge shown in the gun, the CD/XTP debate will be settled.

You are on the right path. It looks like the feed ramp is a tiny bit too abrupt for those particular rounds so the HP meplat is jamming in straight. The FMJ bullet profile is riding up and over that spot.

Let us know how your experiment works out.

Stay safe.

Yeah, sure. I'll get one coming. Thanks

 

[halfmoonclip]

You're going to send me to the shop, to have a hard look at how the AR9 mags present the round for stripping. They are double stack/double feed, which is generally seen as better for subguns.
I've two brands of mags, one works with HPs, the other not.
Kind of a moot point; the gun is mostly for my entertainment. If I want to fend off boarders, I've a Scorp that is cheerfully willing to run about anything.
Moon

 

[gun'sRgood]

Here's the rounds that stick.
The mags that I'm using all work with RN's Some of the other HP's have even larger mouths. not bothering to try more of the pricy stuff until I get a handle on this. I've got a bunch of XTP's also from Hornady that I plan on using for HD. I hope.

 

[LiveLife]

And notice RMR MRP's rounded nose profile/ogive that should help with feeding/chambering as it is essentially RN with tip cut off - https://www.thehighroad.org/index.p...dow-2-rmr-mpr-124-grain.855353/#post-11214645

RMR's MPR compared to old JHP's profile that is more similar to Gold Dot HP profile.

 

[gun'sRgood]

I'm finding out that in the 1980's the sub gun 9's had a feed ramp designed around the RN as HP were not allowed. Second is that JP's short stroke bolt has a poorly designed ejector design. I plan on having a product that can consume all the afore mentioned rounds. Thanks all for the information and help. Hope to have follow up info when adjustments are made. BTW, as much as I have enjoyed Rainier Arms, they will not make the need changes to their barrel.

 

[Demi-human]

BTW, as much as I have enjoyed Rainier Arms, they will not make the need changes to their barrel.

Meh, they’re, okay. I guess.
But worry not, you can make the necessary changes to you barrel. All it takes is a simple bevel, hand done as nicely as you can, doesn’t have to be perfect, to the throat.
Your first picture shows exactly where the bevel needs to start. It could be as shallow as ten degrees, it may not take a 45° angle. A round file and a dowel, a BIC pen even, with some sand paper is all it will take to race ready your carbine for any bullet profile.
Even the least resourceful can find sand paper and a tube. It may take days, but you’ll have done it yourself, with very little chance of over doing it. Be self sufficient! You don’t need nobody!
(Ya know, besides us. We’re here for ya!)

Or buy a proper barrel. It is just a barrel after all.
But where’s the fun in that?

 

[gun'sRgood]

Thanks

Meh, they’re, okay. I guess.
But worry not, you can make the necessary changes to you barrel. All it takes is a simple bevel, hand done as nicely as you can, doesn’t have to be perfect, to the throat.
Your first picture shows exactly where the bevel needs to start. It could be as shallow as ten degrees, it may not take a 45° angle. A round file and a dowel, a BIC pen even, with some sand paper is all it will take to race ready your carbine for any bullet profile.
Even the least resourceful can find sand paper and a tube. It may take days, but you’ll have done it yourself, with very little chance of over doing it. Be self sufficient! You don’t need nobody!
(Ya know, besides us. We’re here for ya!)

Or buy a proper barrel. It is just a barrel after all.
But where’s the fun in that?

Hey thanks! I've actually got a lathe but this is at least a three axis issue. I think it's a problem of knowing how things are supposed to be done has taken some of the fun out of just trying stuff. Talking to my very experienced lathe and mill buddies, I'm getting coaching on how to hand tool the barrel in the lathe for a Z axis. Thanks. Hope to share soon.