Trouble chambering first 2 rounds of my AR Build:

[VariableRecall]

I have a fairly newly put together AR build, that started from a stripped lower that I had filled in. It's an Anderson Lower, with an A2 Buttstock and a 20 inch government profile 5.56 Upper with a 1:9 Twist. I have less than 200 rounds through this upper.

I first had an issue of light primer strikes, but that was fixed easily by getting an extra power trigger spring.
Most likely this next issue was unable to be seen due to my previous issues, or I had not noticed the problem before, but I now can try and diagnose this other problem.

I am having a lot of trouble getting the first round of a 20 or 30 round magazine chambered in my rifle. The 30 rounder is an Okay Industries magazine, and the 20 rounder is an unknown aluminum magazine. I have Pmags but from my previous experience, I believe that they had the same issues too.

Usually I lock the bolt back and let it ride, but even that gives it a fight. The first cartridge fails to get into battery, leaving the rounded lip on the side of the BCG visible. Extraction then needs to be quite forceful, to get the partially in battery case out of the chamber.
This same issue continues often for the second round in the magazine, but after that point chambering and firing the next rounds is completely smooth and painless.

Any idea on what may be going on in there? When I had inspected my BCG, there was some brass debris from the manufacturer that was likely left from testing, but otherwise I don't think there's anything dangerous going on in there. My suspicion is that I've left the chamber a little grimy or the BCG less lubed than it really should.

Can any of you provide some insights into how I can solve this problem? Under-loading my magazines would likely help but that doesn't seem to be the right thing to leave a problem unsolved.

[Winger Ed.]

Provided its clean and there isn't something obvious causing the bolt carrier to drag or hang up--
Just a guess, but the magazine spring might be so strong it pushes up the top round hard enough to drag on the bolt carrier
enough to slow it down.

Mags. & springs are cheap, I'd try another (Known good) or a high end mag.
Or, clip a coil off the spring of one you have if there is a lot of pressure on the follower when its empty.

If that doesn't fix it- the solution might get a little more involved.

[DDriller]

The first thing I would try is to over lube the BCG. AR's don't mind being wet but hate being dry.

[VariableRecall]

I had noticed that the BCG occasionally leaves quite prominent scratches on the brass when it's traveling rearward. Another guess to the issue is that there's grime or a burr, perhaps a bit of brass, stuck in the chamber and causing problems, but considering that the next 18 or 28 respective rounds chamber and fire just fine, maybe that's not the issue...

From what I've heard, Okay Industries mags are pretty reliable, but that one's the only one of its kind that I have. I'll certainly need to go and test my Pmags to see if they have the same issues.

Not to mention, if I need to modify my magazines or download them for reliable use, I may be ignoring a problem that my rifle may have to begin with.

[VariableRecall]

The first thing I would try is to over lube the BCG. AR's don't mind being wet but hate being dry.

I would like to add that when I was at the range my rifle was quite dry. I had used Tetra-Gun Lubricant wiped from a cotton cloth onto the respective parts in a thin film. For next time, I have directly glopped the lubricant onto the BCG and charging handle, and spread them evenly with a cotton cloth. Here's hoping that does the trick for next time!

[kr54]

If you load the magazine 2 short of capacity, does it load the first round ok?

[Gtek]

Just asking and please take no offense, Are you confident of the A2 RIFLE spring length and buffer? I assume these are factory rounds? Open top up and look at extractor, any rub marks on back/outside? Have you tried with only two rounds?

[VariableRecall]

Just asking and please take no offense, Are you confident of the A2 RIFLE spring length and buffer? I assume these are factory rounds? Open top up and look at extractor, any rub marks on back/outside? Have you tried with only two rounds?

My A2 Buttstock came from UTG. It was a complete kit with a Rifle length buffer tube, spring, and plunger.

I'll be able to run some tests next time I visit the range, including under-loading my magazines.
The ammunition that I was using were some Golden Tiger steel cased rounds, and some 55gn soft point reloads with Lake City brass. When the ammunition was fired, it burned clean, ejected just fine, and was satisfactorily accurate, it just seems that the first couple of rounds are causing me a heap of trouble.

So, this next range trip I make, I plan to double check how lubed up my rifle is, and experiment with all magazine types that I have in my collection to figure things out.

Thankfully I have a Maglula StripLula so getting the ammo into and out of those magazines is going to be quite a bit easier than smashing them in by hand.

[kerplode]

Is your carrier well lubed? The bolt should be wet, and the gas rings should also get a drop of oil through the vent holes.

Does the carrier assembly pass the tilt test? Unload the rifle and engage the safety. Hinge the upper open and point the muzzle down at about a 45 degree angle, Stick your finger into the back of the BCG and pull it out the back of the upper about half way, then let it go. It should fall smoothly back into the upper and lock into battery.

I suspect the bit of additional drag on the carrier from the extra-power hammer spring coupled with the probably dodgy action spring might reducing carrier velocity just enough to prevent the bolt from locking after forcing the top rounds out of the mag. The top two from a full mag take the most force for the carrier to strip.

I don't mean to be critical, but parts are not parts, and UTG stuff is airsoft grade junk. Throw that action spring in the trash and buy one from Brownells or BCM.
https://bravocompanyusa.com/rifle-m16-action-spring/

Who made your LPK? In my experience, you shouldn't need an extra power hammer spring to set off Russian or commercial primers.

[Moleman-]

If you sharpie up a cartridge and let it jam as described where it need forcefull extraction, where is the sharpie removed or worn thin on the cartridge? How does it do with factory new brass cased ammo? Is the chamber on the tighter side and you need to use a small base die or polish the chamber? For the case scratches it can be the BCG, mags and very often if you're getting brass glitter with gouges/dings on the shoulders and necks, the locking lugs on either side of the extractor need dehorned. Just dull the sharp inside front corners that are acting like chisels. Don't go crazy removing metal.

[VariableRecall]

Is your carrier well lubed? The bolt should be wet, and the gas rings should also get a drop of oil through the vent holes.

Does the carrier assembly pass the tilt test? Unload the rifle and engage the safety. Hinge the upper open and point the muzzle down at about a 45 degree angle, Stick your finger into the back of the BCG and pull it out the back of the upper about half way, then let it go. It should fall smoothly back into the upper and lock into battery.

I suspect the bit of additional drag on the carrier from the extra-power hammer spring coupled with the probably dodgy action spring might reducing carrier velocity just enough to prevent the bolt from locking after forcing the top rounds out of the mag. The top two from a full mag take the most force for the carrier to strip.

I don't mean to be critical, but parts are not parts, and UTG stuff is airsoft grade junk. Throw that action spring in the trash and buy one from Brownells or BCM.
https://bravocompanyusa.com/rifle-m16-action-spring/

Who made your LPK? In my experience, you shouldn't need an extra power hammer spring to set off Russian or commercial primers.

My Lower Parts kit was from Tom's Tactical, with their premium nickel teflon trigger kit and the rest of the parts provided from the same source. The trigger is great for the price, and has a nice break to it. I'd say it's about 5lbs. I did have to replace the hammer spring cause it were apparently not strong enough. A Wolff extra power spring solved the problem but i can barely tell the difference between the two of them by finger.

I'll try the tilt test when I get the chance. Thanks for the tip regarding that check! When I actually get the chance to make a range trip.
Also, thanks for the tip on a good value rifle spring!

[Gtek]

Extension lugs/ramps and fit into upper. M4 upper, rifle upper? if not already confirmed gut upper and from underneath take a toothpick and from bottom feel transition from into ramps.

[VariableRecall]

Extension lugs/ramps and fit into upper. M4 upper, rifle upper? if not already confirmed gut upper and from underneath take a toothpick and from bottom feel transition from into ramps.

What exactly do you mean by that? the ramps on my upper look fine and don't show any prominent wear. One thing that I did notice is that through my familiarizing with snap caps I had zero issues with feeding rounds. Other than the BCG scratching the anodized coating of my snap caps as it traveled backward, I had no issues. The barrel/chamber seems to be quite the tricky spot to clean! Any tips/tricks to ream it clean of grime when the contours of the barrel lugs and chamber make cleaning awkward?

[Gtek]

Sometimes the grooves (right and left feed ramp area) cut in the barrel extension are narrower or misaligned with the cuts (ramps) in M4 upper, old rifle has a flat ramp in upper. This can create high spot ridges that the nose of bullet can hang on and cause problems with feed. Google M4 verses Rifle feed ramp, there are some great pictures online. A whole bunch of people made parts, I have had instances where maker A's part does not exactly line up with maker B's part. Just helping you chase your problem and not knowing where you are at on build knowledge, no disrespect intended. In regard to cleaning, pop rear and remove guts, I have a link to hold weapon open in rifle vise with muzzle pointed down. I use carb cleaner and spray in gas tube and into extension with all running down out muzzle. Then push a couple to clean/dry, the carb cleaner helps remove carbon, then bore solvent as needed and done.

[Rcmaveric]

I had some issue once in my Grendel. I pollished my feed ramps. I have to two part feed ramp and they didnt line up well. I ground it down to make better angle and pollished to make it look professional and not bubba.

I noticed my cast bullets had dings in them and would catch causing a stove pipe. The lomg 6.5m would catch in the mag while riding up the feed ramps.

If i remember correct you had the match the feed ramp of the barrel to the feed ramp of the upper. No m4 ramps or with m4 ramps. I am not sure what a miss match would cause. All it is the feed ramps extending into the upper or not. Hind site i think it was M4 ramps causing my long bullets to jam. Had i had a shorter ramps the bullets would clear the mag before tilting up i think. But i fixed it with pollished and a slight angle adjustment.

Sent from my SM-G991U using Tapatalk

[VariableRecall]

Sometimes the grooves (right and left feed ramp area) cut in the barrel extension are narrower or misaligned with the cuts (ramps) in M4 upper, old rifle has a flat ramp in upper. This can create high spot ridges that the nose of bullet can hang on and cause problems with feed. Google M4 verses Rifle feed ramp, there are some great pictures online. A whole bunch of people made parts, I have had instances where maker A's part does not exactly line up with maker B's part. Just helping you chase your problem and not knowing where you are at on build knowledge, no disrespect intended. In regard to cleaning, pop rear and remove guts, I have a link to hold weapon open in rifle vise with muzzle pointed down. I use carb cleaner and spray in gas tube and into extension with all running down out muzzle. Then push a couple to clean/dry, the carb cleaner helps remove carbon, then bore solvent as needed and done.

Thanks for the clarification. I can see how different barrel profiles may cause some conflict with other BCGs. The BCG I have came with my rifle as a complete upper kit, so i doubt they would have given me a BCG that was out of spec for that thing. As far as I'm aware, it's a generic mil-spec BCG with no real distinguishing features other than given a standard black nitride finish.

Unfortunately I don't have a vice, but I'm pretty sure I've got carb cleaner handy. That sounds like a very stinky and human unfriendly, but effective method of cleaning. I doubt I could have put much grime into an upper that new, but when the time comes when it gets truly filthy, that sounds like a solid way to clean things out.
Would Brake Cleaner do a similar job? I'm pretty certain that both of them are quite nasty pressurized liquids that evaporate quickly and tear through whatever fouling it comes across.

[VariableRecall]

I had some issue once in my Grendel. I pollished my feed ramps. I have to two part feed ramp and they didnt line up well. I ground it down to make better angle and pollished to make it look professional and not bubba.

I noticed my cast bullets had dings in them and would catch causing a stove pipe. The lomg 6.5m would catch in the mag while riding up the feed ramps.

If i remember correct you had the match the feed ramp of the barrel to the feed ramp of the upper. No m4 ramps or with m4 ramps. I am not sure what a miss match would cause. All it is the feed ramps extending into the upper or not. Hind site i think it was M4 ramps causing my long bullets to jam. Had i had a shorter ramps the bullets would clear the mag before tilting up i think. But i fixed it with pollished and a slight angle adjustment.

Sent from my SM-G991U using Tapatalk

So far I have not tried loading excessively long projectiles in my rifle. The highest I've gone was 56gn Golden Tiger. A 1:9 twist means that I can go pretty light in terms of projectiles down to 40gn, up to about the edge of 65gn or so, as far as I'm aware. My projectiles had been sticking between 40 and 55 grains.

I'm not really sure if it would be worth polishing my feed ramps if it means removing the finish that keeps my bits in tip top shape.

[JimB..]

Just to clarify. Fully loaded magazine, release bcg from lock, rounds fails to fully chamber.
Drop the magazine.
Extraction of the round is difficult, correct?

Now strip a few rounds from the mag. And reinsert.
Feeds fine? If yes, does a round extract easily by hand?
If it doesn’t feed fine in this test, when does it feed fine?
Whenever you get it to feed fine, can you then easily extract a round by hand?

[VariableRecall]

Just to clarify. Fully loaded magazine, release bcg from lock, rounds fails to fully chamber.
Drop the magazine.
Extraction of the round is difficult, correct?

Now strip a few rounds from the mag. And reinsert.
Feeds fine? If yes, does a round extract easily by hand?
If it doesn’t feed fine in this test, when does it feed fine?
Whenever you get it to feed fine, can you then easily extract a round by hand?

At the time, I was more worried about staying safe at the range and ensuring I would get my money's worth for the reservation. I didn't directly troubleshoot the mags like so since I had only brought their contents to the range, besides the rifle and ear/eye protection.
From my recollection, when the round had failed to go into battery, with the rounded lip of the BCG visible at the ejection port, ejection was stiff. I had to mortar it on a table to ensure vigorous ejection. I didn't try the forward assist, but I think that could have helped. I'd assume a forceful series of strikes to the forward assist would inch the BCG towards its destination?

When I was at the range, I had not attempted to see if a down-loaded mag would improve reliability. However, I can assume that down-loading the magazines will help as the rest of the magazine worked just fine after the first two caused a lot of trouble.

When I had the issue with light primer strikes, I was able to eject rounds just fine when the issues occurred. If anything, a light primer strike would be far more dangerous for myself and others than a failure to feed.

[JimB..]

I’m hung up on the ejection issue. If it fails to feed and can’t be ejected easily when the mag is removed then there is a more serious issue than the mag spring being too strong.

None of the troubleshooting requires firing a round. Keep the gun pointed in a safe direction, as always, and see what will or won't feed. Can likely get this figured out before you head back to the range.

[Moleman-]

Jim is correct. That's why in post 10 I suggested sharpieing up a case including the bullet and seeing where the cases are sticking. Having to mortar the action to unlock it is an indication that something is off. Could be the ammo or it could be the chamber. A set of headspace gauges would be nice, but they won't tell you if the chamber is slightly narrow in some spot, just length. It really sounds like this has been an issue the whole time with the light firing pin strikes. The carrier wasn't getting fully seated and was taking up some of the energy of the hammer when it seated that wasn't getting transfered to the firing pin leaving you with light primer strikes.

[bangerjim]

Lube......lube.....lube! One of my new AR's a few years ago fired 2 rounds and the 3rd one was stuck tight. I had to tear it totally down. I was shocked to find the amount of factory crud that was left in there during the manufacturing process. After a complete bath, and good CLEAN lube job, it now cycles perfectly.

[VariableRecall]

I’m hung up on the ejection issue. If it fails to feed and can’t be ejected easily when the mag is removed then there is a more serious issue than the mag spring being too strong.

None of the troubleshooting requires firing a round. Keep the gun pointed in a safe direction, as always, and see what will or won't feed. Can likely get this figured out before you head back to the range.

I'll be certain to troubleshoot the issues once I visit the range, but I suppose one thing that I could try without going to the range is loading up 18 or 28 rounds in a magazine, and filling the last two with snap caps. Sure, it gives me the willies to insert a magazine with some live ammo inside it outside of a range or a life or death situation, but it may be the only way to try in the meantime. If anything, once the round is successfully chambered, I could just drop the magazine so the distance between the rifle and live ammo is increased significantly. Even if I were to chamber another round after ejecting the first, the second round would be a snap cap, so I at least have that last safeguard. Plus, I could just try this in any of the magazines I have on hand.

I'll be sure to report back my findings once I've tried them.

[VariableRecall]

Jim is correct. That's why in post 10 I suggested sharpieing up a case including the bullet and seeing where the cases are sticking. Having to mortar the action to unlock it is an indication that something is off. Could be the ammo or it could be the chamber. A set of headspace gauges would be nice, but they won't tell you if the chamber is slightly narrow in some spot, just length. It really sounds like this has been an issue the whole time with the light firing pin strikes. The carrier wasn't getting fully seated and was taking up some of the energy of the hammer when it seated that wasn't getting transfered to the firing pin leaving you with light primer strikes.

The light strikes being related to the system being less than perfectly seated is something I hadn't considered. I did note that when I had a failiure to fire, there were no marks on the primers, so likely being out of battery prevented the firing pin from being hit properly in the first place (Thank goodness!). When I still had light primer strikes, the firing pin had solid hits on the primers, but not enough to detonate them, so at least they were in battery when that happened. Another thing I noted was that almost all of my reloads worked perfectly since they were using SRP's instead of extra-hard military primers.

I have yet to take my upper to a gunsmith that may have some headspace gauges, but that sounds like a smart thing to do, potentially.

[VariableRecall]

Lube......lube.....lube! One of my new AR's a few years ago fired 2 rounds and the 3rd one was stuck tight. I had to tear it totally down. I was shocked to find the amount of factory crud that was left in there during the manufacturing process. After a complete bath, and good CLEAN lube job, it now cycles perfectly.

Here's hoping that's all I need to do! What's your preferred AR lubricant? I've got Hoppe's Gun oil, Ballistol, and Tetra-Gun Lubricant handy for those purposes.

[JimB..]

If you’re nervous about chambering a live round, separate the upper and just drop a live round straight into the chamber. Does it go in all the way, can you spin it, extract it easily.

Moleman’s suggestion is good, mark the brass and look for where it rubs. Always best to find the problem first rather than just trying stuff.

[Moleman-]

The failur to fire and light strikes can still be the same thing. Take a look at the cam track on the carrier. Either way you look at it, short run-turn-short run. The short run at the bolt side lets the carrier build up speed/energy to jerk the case free of the chamber because of the lack of primary extraction. The one of the buffer side is the firing pin safety. If the bolt isn't completely turned freely enough to allow the carrier to go forward that last 1/8" or so the firing pin will bottom out on the carrier and not the bolt tail when hit by the hammer. If it's close some of the energy will be used to push the carrier forward and still leave a lighter than normal dent in the primer.

The HS gauges may show a tighter than spec chamber, but won't tell you if it's undersized on a diameter which is more likely since it passed a HS check before leaving the factory. I've found some of the cheaper barrels are run with pilotless reamers which often have rifling on one side of the freebore, but also have tight spots in the neck or near the base even with factory LC cartridges. I've had AR-Stoner and BCA barrels that would accept factory LC cartridges but not other surplus or known good reloads as the chamber base dia was too narrow. I will no longer buy a nitrided barrel from them as this issue can't be fixed by running a HSS chamber reamer in one of those hard barrels. They're basically using their tooling past it's useful life. That is why I suggested sharpieing up a cartridge to see where the tight spots are. If you have to mortar a cartridge to eject it, it's tight somewhere and the worn off sharpie will tell you where.

For lube M-pro-7 or some version of clp is what I use.

[popper]

Extraction then needs to be quite forceful
Doesn't make any sense unless the case neck gets bent. Hammer shouldn't even touch the BCG. Buy an AR chamber brush to clean it. Run the BCG wet like dripping to get everything to seat/break-in. Strong mag springs or a fully loaded mag can put extra pressure on the carrier bottom, slowing it down. Should never be any brass shavings inside the BCG. Bad 'lips' on the mag can cause a double feed, and fail to feed. 1st rnd is from right side, lips have to center it into the chamber. Left side is next. If lips are not correct, get nose up or nose down jams. Rough case extractor lip can also cause a double-feed.

[Texas by God]

Lots of great suggestions here. If you want to safely cycle live ammo for clues; just remove the firing pin from the BCG and do it. I concur about oil, I use it in the two vent holes on the bolt- hi tech wonder lube, 3in1, or motor oil from a dipstick- all work.

Sent from my SM-A716U using Tapatalk

[BK7saum]

I may be the odd man out here, but my thoughts are, just run 27 rounds in a 30-rounder and 18 in a 20-rounder. Thats all i charge in the mag anyway. As the upper gets broke in, this may be a non-issue. I have never charged my mags to full capacity in anything, rifle or pistol. The springs are designed to take it, but why? If 27 or 18 rounds won't solve the problem...pretty sure the extra 2 or 3 isn't going to make the difference.

[Moleman-]

If you remove the firing pin as suggested you run the very real risk of having the cam pin rotate and bind up the upper. It's a pita to fix.

[Texas by God]

If you remove the firing pin as suggested you run the very real risk of having the cam pin rotate and bind up the upper. It's a pita to fix.Wow. That makes sense. I did it once and got away with it, and my reply was based on that experience. Thanks for the heads up!
OP, sorry for the wrong advice. Oil the BCG and load the mag down by 2 as mentioned and it may work.

Sent from my SM-A716U using Tapatalk

[Gtek]

Are you sure, is the rectangle pin head not contained in orientation by internal channel of charging handle?

[BK7saum]

Are you sure, is the rectangle pin head not contained in orientation by internal channel of charging handle?
No. Once you remove the firing pin, the cam pin is no longer retained and is free to rotate and move up and down in the cam slot.

And yes, the cam pin cannot fall out but it can rub, gouge and turn which may damage the interior of the upper receiver

[Moleman-]

The issue is the unsupported area where the cam pin turns through the cam slot where the half moon cutout is if you look through your ejection port. The cam pin is free to rotate or lift up as BK&saum mentioned. Sometimes you can giggle it back close enough that it'll open. There's a coathanger wire trick, dental pic through the ejection port or gas tube hole (got to temove gas tube) and as a last resort you can pull the barrel to give you more room to get at it. Google "assembled ar15 without firing pin". It's one of those things you usually only ever do "once".

[VariableRecall]

I may be the odd man out here, but my thoughts are, just run 27 rounds in a 30-rounder and 18 in a 20-rounder. Thats all i charge in the mag anyway. As the upper gets broke in, this may be a non-issue. I have never charged my mags to full capacity in anything, rifle or pistol. The springs are designed to take it, but why? If 27 or 18 rounds won't solve the problem...pretty sure the extra 2 or 3 isn't going to make the difference.

For me, thankfully I have an easy method of getting rounds in and out of magazines. Since I can strip in 10 rounds at a time with a firm shove, I just fill it up to capacity and push in. The StripLula has a nub on the rear that can push cartridges out of the magazines easily. It's basically a re-usable stripper clip with a finger support to shove cartridges in.
https://www.maglula.com/product/m-16-ar-15-striplula-5-56-223

However, it's probably just as easy to leave a couple of rounds out in my testing. First, I'll just run it as-is, then goober it up and see how much of a difference it makes. Then, I can move to more difficult measures.

[VariableRecall]

If you remove the firing pin as suggested you run the very real risk of having the cam pin rotate and bind up the upper. It's a pita to fix.

Another solution to this problem is to find an extremely cheap, sacrificial firing pin, and file it down until it's impossible to actually have it strike a primer.
Would that be possible? Or would a firing pin that short cause other issues? At least it could support the cam during its travel...

[Moleman-]

Another solution to this problem is to find an extremely cheap, sacrificial firing pin, and file it down until it's impossible to actually have it strike a primer.
Would that be possible? Or would a firing pin that short cause other issues? At least it could support the cam during its travel...

You can, but it won't eliminate all possibility of the gun going off if for example you have a high primer. You'd just need to remove the tip so the pin no longer fits through the face of the bolt and is recessed a little bit.

The factory LC cartridges I mentioned are generally on the smaller side for case body diameter just like factory R-P with good quality control. Often surplus or steel cased ammo isn't as small of a dia and doesn't have as good of quality control. Since you have reloading equipment, make up a powder and primerless cartridge for the sharpie test. It's a good diagnostic tool to show you where the cartridge is tight in the chamber causing forcefull chambering or extraction. When I make a wildcat barrel and the dummy or unfired cartridges require more effort than normal to extract (if it's not visible on the cartridge) the sharpie test is the first thing I try.

[Baltimoreed]

Clip a magazine spring coil and try it, clip another coil and try it until it runs or load your mags down a few rounds or try an ar 10 buffer spring. What happens if you load a round and then insert your magazine loaded full?

[VariableRecall]

Clip a magazine spring coil and try it, clip another coil and try it until it runs or load your mags down a few rounds or try an ar 10 buffer spring. What happens if you load a round and then insert your magazine loaded full?

I think I would rather try that with a spare magazine spring. I know I can find some at a sporting goods store, but I think an easier route is to also test by loading less rounds in a magazine. I think that it would be best to ensure that my rifle fits the standards of any old AR pattern rifle.

[VariableRecall]

You can, but it won't eliminate all possibility of the gun going off if for example you have a high primer. You'd just need to remove the tip so the pin no longer fits through the face of the bolt and is recessed a little bit.

The factory LC cartridges I mentioned are generally on the smaller side for case body diameter just like factory R-P with good quality control. Often surplus or steel cased ammo isn't as small of a dia and doesn't have as good of quality control. Since you have reloading equipment, make up a powder and primerless cartridge for the sharpie test. It's a good diagnostic tool to show you where the cartridge is tight in the chamber causing forcefull chambering or extraction. When I make a wildcat barrel and the dummy or unfired cartridges require more effort than normal to extract (if it's not visible on the cartridge) the sharpie test is the first thing I try.

I do have a large variety of headstamps of .223 brass to try out. After a rather scary batch of badly loaded .223 rounds, I now have an LE Wilson Case Gauge and that has made a huge difference in keeping my loaded ammo consistent. I can also cross-reference the case gauge with my own barrel as well when I get the chance.
I can try the sharpie test with a snap cap, so that there's no chance of a primer going pop in my presence.

[Moleman-]

The factory new LC or RP ammo being on the smaller side for case body diameters can be used to see if it chambers fine and extracts without effort. That'll help point towards a chamber diameter issue. Once fired they are no longer on the smaller side as they've been fireformed to a chamber. If that chamber is generous they might even need run through a small base die to cycle smoothly in a standard chamber. So as a diognostic tool they're only useful if factory new. Commercial snap caps are even more undersized and sharpieing one up will tell you little or nothing. A dummy round with the components you're using and sized by your sizing die would be more useful.

[VariableRecall]

The factory new LC or RP ammo being on the smaller side for case body diameters can be used to see if it chambers fine and extracts without effort. That'll help point towards a chamber diameter issue. Once fired they are no longer on the smaller side as they've been fireformed to a chamber. If that chamber is generous they might even need run through a small base die to cycle smoothly in a standard chamber. So as a diognostic tool they're only useful if factory new. Commercial snap caps are even more undersized and sharpieing one up will tell you little or nothing. A dummy round with the components you're using and sized by your sizing die would be more useful.

I do happen to have a decent amount of brass left over from my previous range trip. I could compare that between the Golden Tiger that I have remaining and the reloaded ammo that I have lying around. I am not exactly spoiled for choice but I think that it would be worth something to try out.

[kerplode]

Were you able to get it working?