[jbrillhart]

hi all - i'm new so if i'm asking a question that's already been aswered i appologize. but here goes:

i have 2 carbines. an inland blue sky inport, and a new fulton armory built on a fulton armory
barreled receiver with matching bolt. i use usgi 15 rnd and aftermarket 30 rnd mags for both ( the same ones). both will feed fmj, jsp, hornaday short jacket, and hornaday critical defense flawlessly. the problem is tying to use hornaday xtp bullets. these are seated at the recommended seating depth giving a col of 1.550. they feed flawlessly in the inland with the same magazines, but they will not feed in the fulton - they jam into the feed ramp. i called fulton and talked to one of their armorers and he said the original varied considerably with respect to the feed ramp dimensions and that could explain why they work in the inland. also it could be that the feedramp on the inland has so much wear that the xtps work. by the way, this gun has been shot so much that i had to turn down on oversize gas piston on my lathe and then harden it so it wouldn't shortrecoil. works fine now. fulton doesn't recommend any bullet type except fmj profile officially. but that he tried putting the follower sping in backwords, bending front feedlips, and bending the top of the follower spring to change its impact point point on the follower thus changing the angle the cartridge sits at in the mag. i'm reluctant to bend feedlips because of the ease of messing them up so if i attempt that, i'll use a new mag dedicated to that purpose. has anyone tried these methods and with what success? any other ideas.? as a ps ALL the ammo i use except for the critical defense stuff are reloads and they all work well except this one example. would welcome any ideas/ suggestion. thank you all. jbrillhart

 

[GunGeek]

I'm not familiar with the current non-GI Carbines so I can't speak to that particular rifle; but my experiences with commercial carbines has not been good.

My experience with loading JHP bullets in GI carbines has taught me that Cartridge Overall Length is absolutely critical. A COL of 1.550 seems awfully short to me. The XTP is a very short bullet so you'll need to seat it WAY out to get a similar COL to the standard FMJ round. And you're not looking so much for overall length as you are trying to match the length of where the bullets hit the feed ramp.

I don't know how to explain it well. With a FMJ it's not typically the tip of the bullet that hits the feed ramp, but just a little below that on the ogive. But an FMJ has an ogive, where a JHP is more conical in shape. So you have to seat that JHP WAY out there to emulate the feeding of a FMJ. From the base of the case to the point where a FMJ hits the feed ramp, that one little contact spot just slightly below the very tip; THAT is your measurement. But you're just not going to be able to emulate that with a very short, conical 90 grain JHP.

The 90 grain XTP is not a good choice for the .30 Carbine
When you start looking at factory JHP rounds in .30 Carbine you're going to find that most everyone is sticking in the 100-110 grain range because the bullet length is critical in the .30 Carbine, and the 90gr XTP isn't a bullet that has enough length to be ideal in an M1 Carbine. All the bullets intended for the .30 Carbine tend to be a little long; much longer than the XTP.


So my recommendation:

Put the calipers down and seat to fit the magazine...

Start with the bullet seated as far as you can get it out of the case and still fit into the magazine. All of my JHP rounds require my bullets to sit way out in the cartridge to emulate the FMJ feeding characteristics. Taking COL measurements are for you notes for future loads, but they won't help you in developing the load. You'll have to seat the bullet far enough so the magazine release timing is proper, and that's a small window. Since the ogive shape and bullet point shape is very different between FMJ, Soft Point, and various JHP's actual MEASUREMENTS are useless. IF the XTP will work at all, I think you're going to find that it will be seated out to somewhat of an extreme. Once you find a seating depth that works in both rifles, NOW you can take a COL measurement, mark that down for future loads of the same bullet.

 

[jbrillhart]

thank you very much. sounds like excellent advice. i have tried seating further out with inconsistnt results - trial & error. it sounds lke your approach will work, if indeed it will work at all. as you said the xtp is pretty short. to be honest i wouldn't bother with it except its considerably faster than the standard round and makes a very nasty hole; considerably better than the others. but if it's not reliable it's not worth much at all. thanks again

 

[Captain O]

If you are still having misgivings about the Hornady XTP, you many want to look into the Underwood "Extreme Cavitator" round designed to provide excellent penetration With more than adequate cavitation due to the bullet design. The solid copper bullet relies upon hydraulic pressure to create a permanent crush cavity that rivals any jacketed bullet on the market today.

Look it up. I'm certain that you'll be as impressed as was I.

 

[smokpole]

Before doing anything else, look at the feed ramps. Is the ramp on the Inland polished? Is the ramp on the FA polished? If the answer is that the Inland is and the FA is not, then polish the feed ramp and see how much of a difference it makes. That could be the cause of the hang ups.