Just wanted to pick some brains here and see if I missed anything. I've got a decent condition Quality Hardware carbine that I replaced the recoil spring, and tried new mags, but still get failures to feed. I occasionally get failures to eject, but I haven't taken the bolt down yet to maybe replace the ejector as that only happens now and then. I'm mainly getting feed issues, at least one per mag. So recoil spring changed, and tried new and some GI mags, is there anything else I can check to maybe solve this issue?

Thanks

What ammo, and what manufacturer / capacity mags?

Disassembling/cleaning/lubricating the bolt can't hurt. A sticky extractor won't help feeding. Last Carbine bolt I took apart had a broken extractor spring and extractor spring plunger that were not obvious when assembled. Fed much better once that was remedied.

What operating slide spring did you put in? GI, Wolff or?

Which type magazine catch is presently installed in your trigger housing?

Probably worn piston and piston nut... or they are loose.

Ammo is ball, honestly, I forget what brand, maybe Privi? Mags are GI and aftermarket, malfunctions with either. I don't know which mag catch is in it, late production if I remember the differences correctly. Recoil springs I've tried are Wolf and new, surplus GI. Well lubed but haven't taken the bolt apart yet, I need to get a tool. Looks like I have several points to inspect...

Are you positive that the cartridges are not handloads? When I first started reloading .30 Carbine I found that the length of the brass IS critical and also the depth of the primer. If the brass is trimmed too short or the primer is set too deep it will not fire.

Positive. I'm saving my brass, but all I have at the moment is some factory stuff I picked up last year. I did have Shuff's go over it right after I got it, and I do remember checking the piston and nut and that seemed ok. I guess I need to go over the bolt at this point.

If he or you didn't measure it then you don't know if it's ok.

You're right I didn't measure it, just checked to make sure it wasn't loose. I' don't know if Shuff measured it or not. I plan on going over the whole thing this week, just wanted to see if there was anything I was missing. I always read about how reliable carbines are, so it's frustrating mine has issues and I can't seem to identify the problem. I really want this thing to run like everyone elses.

well if you can't figure it out...I know a guy...

Rebuilding the bolt would be my next thought if you changed the recoil spring. Try here

https://www.m1garand.com/store/m1_carbine_bolt_rebuild_kit.html

I keep this on hand if I think I need it

https://www.fulton-armory.com/spare-parts-kit-m1-carbine.aspx

I would also try a different brand of ammo. IMO PPU .30 is a tad underpowered. I used to get 1 FTF every 50-100 rounds when I was using it.

Also, are you running it "wet". I tend to make sure I run a drop of oil on the bolts when I shoot a M1 Carbine.

Last step would be the gas piston. They do wear out. I'm not familiar with how through Shuff's is when they check a Carbine or Garand out, I've always used Fulton Armory and consider them excellent to deal with and the best in the bussiness

I'm literally guessing on the ammo, I dumped it into an ammo can to take to the range, which got delayed for several weeks. But I'm pretty sure it's PPU. Yes I do lube it well. Gonna check that piston and get the bolt kit, thanks for the info!!

Commercial .30 Carbine ammo can be hit or miss. I love S&B when I can get it. Armscor I've had good luck with but someone on the Carbine Collectors forum had issues with it.

PPU is decent but as I mentioned is a tad underpowered IMO. Aquila is also underpowered and caused the most FTF/FTE's of any ammo I've used the past few years. All of my USGI carbines have seen a Fulton Armory inspection and have had worn parts replaced, my 1968 Plainfield I rebuilt using the FA kit I linked.

I'm betting ammo is not your problem. When I bought my first carbines a couple of years ago I bought a few hundred rounds of PPU to shoot for the brass. It shoots the same POI as my handloads that run a 110 gr. FMJ 2000+/- fps. In regards to handloads, anything within reason cycles the action and feeds, even loads in the 1600-1700 fps range.

 Next time you shoot, try this- Hold upward pressure on the bottom of the magazine as you fire. Doing so puts the top cartridge in the magazine closer to the center of the chamber when the bolt strips it from the magazine. If doing this corrects your failures to feed, I'd replace the mag catch. A worn or sloppy catch won't hold the magazine up high in the magazine well.

 As far as your FTE's, definitely clean and re-spring your bolt. A Q-Tip and some Hoppe's #9 works great. By far the least expensive place for M1 Carbine springs, tools, etc. is Sarco Inc.. I buy all my springs and tools there, and have for 2 years now, and have been 100% satisfied. They have an entire spring kit for $6.95, a replacement extractor for $17.00 (if you need one)the bolt disassembly/assembly tool for $22.50. Apex Gun Parts is also a good place for parts, especially if you want to buy parts of certain makes.

Thanks ggibs! I was going to mess with it this past week, but my on going health issues reared their head and kept me house bound. This weekend hasn't been much better. I do plan on getting new springs, I could have sworn I got new ones and sent along to Shuff for him to go over it, but I don't see in my records any receipts for springs. The mag test is interesting, because I'm getting issues from surplus and new mags so I'm wondering if it could be the catch. I had to send a complete trigger housing to Shuff's because the magwell was bent so badly you couldn't get a mag out once it was inserted. Shuff just swapped all the parts over to the new housing, so that's something else I'll have to check.
I really appreciate all the input, I can easily figure out issues with ARs, I'm even pretty good with M1s, this is my first carbine so I'm learning as I go.

Many years ago I had a similar issue with a M1 carbine I purchased from a well respected CMP forum member. The CMP had already stopped selling carbines except thru their online auction. The gun was spotless, the seller had never shot it. Everything seemed perfect but I was getting numerous FTF's and FTE's. The seller recommended I disassemble the bolt to inspect & clean. USGI M1 carbine bolt tools were easy to track down and thankfully YouTube had the videos on how to disassemble/reassemble the M1 carbine bolt with the tool.
My issue ended up being dried grease or cosmoline. Cleaned it up and everything turned out great. Luckily there are NOS parts still available if needed.
Get yourself a bolt tool and check everything out in the bolt.
Good Luck!

Finally! Been sick as a dog for...ever, but finally got a chance to break down the carbine again after another test firing. I had ordered some more parts and got them in. I replaced the ejector and spring, and the extractor and spring.(Boy even with the tool that's a chore! Could they have made that plunger any smaller??) Anyway after a good scrub and lube I took it to the range.....dammit! Still getting extraction / ejection issues!
I contacted Jeremy2171 and even sent him pics of the brass I had stick in the chamber. He suggested I polish the trigger. Hmmm...never done that before. I managed to get a light rigged up so I could actually see in the chamber and wow, like the inside of a culvert. Well, here goes...
Scrub, scrub, scrub. Then rig up my polishing operation and 30 minutes later I have a shiny culvert! There appears to be concentric circles nearly the entire length of the chamber. But I thought, let's see if this helped. Back to the range and wow, even using KCI 30 rd mags, I had ONE failure to extract / eject in three mags!! Despite my culvert pipe chamber! And I found out this thing is a shooter! I was only able to use a 25 yd range, but I got the thing dialed in and literally ate the 10 ring out of the target. She shoots a little low, but probably dead on at 100.
I plan on keeping this barrel, despite the chamber looking so rough, and may try to polish it some more. Thanks to everyone who offered advice, especially Jeremy, who even gave me the gas nut and piston measurements I didn't have. It all came together, and I now am a happy camper, I have a carbine that runs reliably!

1 failure with a KCI 30 round mag is a good day at the range IMO. I would get some 15 round mags and stick with those.

I have several 15s, GI and KCI, fortunately I've had good results with the 30s, I just down load them to like 25-28 and they seem fine.

I keep meaning to try a couple of the KCI 30 rounders but with the price of .30 Carbine right now I'm not shooting my Carbines much.

I saw some 30 carbine at Georgia Arms, they list it available in 200 rd cans for 175. It is pricey tho...

I'm waiting to see what the CMP is supposed to be getting in this spring, hopefully it'll be priced better