.30 carbine and O.A.L.?

Sure sounds like the bullet is stopping on the lands and should be seated deep enough to fit.
I can't testify as to your powder charge but you are below Start for a 110 JSP.

First are you trimming the sized brass if needed. These are straight walled BUT they will grow in length. Sounds as though your bullet is just touching the lands so it does not go in fully. Loading them shorter will work. I have noticed the FMJ that the rifle was designed to use has more of a point and all the lead bullets have more of a rounded shape and you experience the results of this using a standard OAL.

I have the same problem with Armscor 110 FMJ bullets, in fact I had some of the same issues with their factory ammo as well. A few boxes had OALs all over the place. They average 1.658 - 1.668 in the sample I measured. Average was 1.665, and it needs to be shorter than the published 1.680 as the bullet profile is more blunt nosed than any surplus or Remington fmj I've used. This is my first test run, I have 15 loaded up at 1.665 with 14 grains of H110. Still need to get out and run them across the chronograph and see how they do. I think you're on the right path, have you made up some dummy rounds at your new OAL to see if the bolt will close on them?

What’s the diameter of the bullets you’re using?
With my two carbines, some older foreign brass and milspec brass with .311” bullets will cause hard chambering.
Likewise as Frogo mentioned, trimming the brass to minimum spec.
My guns cycle and function better at 1.665 to 1.670” though milspec is 1.680”.
The shorter length allows the bolt to get a better running start to push the round up the feed ramp, it seems.
I use the Lee 93gr RN with Harbor Freight powder coat sized to .311”. At .309” I get better cycling but accuracy is much better at .311”. I use 11.2gr of #2400 as it throws brass over my right shoulder rather scattering it forward and right as H110 does.
(The Lee mold is a 6-cav and “rains” good bullets...)
My guns also feed and shoot the 90gr SWC and 100gr RN, But, those are 2-cavity molds ...sigh..

Having trouble with factory feeding may be problems with incorrectly bent feed lips on the MAG. I have had this problem. That was with WWII hardball, factory mags, and an origional IBM, so I realized it was the MAG.

I suggest you buy a case length/headspace gauge veto check for reloads.

https://www.theshootersbox.com/30-C...ew-Patented-Tri-Step-Face-Design_p_33499.html

The above is just one example. If you find one from L.E. Wilson or Lyman even better but the ones I saw were out of stock.

Like others have said, it sounds like you're seating the bullets too long and they're jamming into the rifling and not allowing the cartridge to fully chamber. The good news is, it sounds like your carbine is doing its job and not allowing the primer to be fully struck, thus preventing an out-of-battery discharge. This situation would be very easy to determine by simply chambering one of the rounds in question, then ejecting it and looking for rifling marks on the bullet.

Don't get hung up on using one o.a.l. as every bullet can be different. I use 1.680" for Remington 110 gr. FMJ's and Hornady 110 gr. FMJ's and SP's because those bullets have a profile very similar to the military 110 gr. FMJ and are for the most part these bullets are all the same length. I shoot a lot of cast bullets out of an RCBS 30-115-SP mold. These typically weigh 115 - 118 grs. and I use the same data as I use for 110gr. FMJ's and get very similar velocities.

If you don't already have one, a chronograph is indispensable for load development.

35W

30 Carbine seating depth depends on the bullet being used. For traditional 110 grain RN, 1.67 - 1.68 works just fine.

However, this length will cause a failure to feed on my Lyman # 311359 115 cast bullets. That bullet calls for a 1.635 depth. Feeds perfectly. This same depth is also needed for 100 grain semi-jacketed plinkers as well. Perfect feeding…in my experience…

Bayou52

Are you sure-- absolutely sure -- the cases themselves haven't grown/lengthened out of spec?

Eagle103 said:

One of my MK III's on a chilly day.

View attachment 1016022

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Mosesiii21 said:

Currently using 115 lead coated Bayou bullet so i was slightly reducing charge because i cant find data on 115gr, only 110gr bullets. Thanks.

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For data on the 115 grain lead cast bullet in the 30 carbine, see p. 209 of the Lyman Reloading Handbook, 48th Edition, 2002:

https://archive.org/details/LymanReloadingHandbook48thEdition2002Ocr_201902/page/n210/mode/1up

Bayou52

Mosesiii21 said:

The new AO M1 Carbine definetly works when i seat bayou bullets around 1.62. Problem seems to be solved. Now time to finish breaking her in.

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Glad to know this because, well.....evidently, some time ago, I ordered some of the Bayou Bullets like you're using, and now they've shipped. Why I ever ordered them, I don't know since I cast my own. Anyhow, I got an email today and they should be here probably Monday.

35W

My .30 Carbine bullets from Bayou Bullets arrived Saturday.



They're somewhat similar in profile to a 110 gr. FMJ, but have a longer bearing surface which requires them to be seated a bit deeper than their jacketed counterparts, and I settled on 1.665"-


My go-to powder for my home-cast bullets is AL2400, so that's what I started with.

In the IBM-

12.0 gr.- 1795 fps, 31 es; 5" 5-shot group @ 100 yds.; 10" low with 100 yd. sight; "On" with 250 yd. sight
12.5 gr.- 1851 fps, 36 es; 3.5" 5-shot group @ 100 yds.; 6" low with 100 yd. sight
13.0 gr.- 1925 fps, 57 es; 4" 5-shot group @ 100 yds.; POI was pretty much "On" with 100 yd. sight.

In the Iver Johnson-

12.0 gr.- 1812 fps 52 es; ~3" 5-shot group @ 100 yds.; ~4" high @ 100 yds. with 100 yd. sight.



I then swung over to the 200 yd. gong figuring it would be easy to work it over. Nope. I never got more than one hit out of five shots. Very perplexing. Then I took a closer look at the bullets, specifically the bases, and found the sprue cuts were ALL off center-



With any bullet, the consistency of the base is of utmost importance for accuracy and with the sprues off center accuracy deteriorates at longer ranges. Also these bullets are a bevel base design which, while making bullets drop from the mold more readily, do not help with accuracy. But that's the bad news....

The good news is-
1) They're more than acceptably accurate for 100 yds. and less shooting,
2) After almost 50 rounds through my beater IBM with its lightly pitted bore, there was ZERO leading. I mean NONE!
3) Best of all they're $35 for $500, $69.50 for 1000, or $277 for 4000 and shipping is a flat $15 whether you buy 500 or 4000.
I will definitely be keeping a few hundred of these around for plinking and practicing.

35W

Mosesiii21 said:

The new AO M1 Carbine definetly works when i seat bayou bullets around 1.62. Problem seems to be solved. Now time to finish breaking her in.

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I ran into this exact same issue a while back with Armscor bullets in my 1943 Inland. The regular slender taper of the original military profile bullets (Remington/PPU/Hornady) could actually be seated long and still work, while the more blunt taper of the Armscor bullets kept hitting the lands until I got to about 1.62”.