M1 Carbine OAL Help

[jasperman]

Hi there. Long time reader (and fan), first time poster.

I've read everything I could find here on this subject and I learned tons! Thanks to all.

I have one thing that confuses me, and I'm surprised no one else has brought it up.
I'm using the Lee C-309-120-R. At OAL 1.600, the case mouth just barely covers the top lube groove. At 1.680, the case mouth is solidly in the driving band between the grooves (leaving a lube groove fully exposed).

It seems that to get a good seat, this bullet wants to be at OAL 1.570.

None of it seems to 'look' right.

I know there are a lot of you out there using this bullet. Where are you seating it? Maybe a few of you could post pics of loaded rounds.


BTW, my brass is at 1.277.

Thanks in advance for your help.

[WILCO]

Good question. What powder are you using???

[Lead Fred]

You need two measurements

one is the chamber, the other is the OAL.

If you trim your cases to sammi standards, you may be cuting them too short, and when you go to get maximun OAL, your case is too short.

You need to get a sinclair chamber guage and measure your chamber, then cut your cases to 010 of the end of the chamber (which is twice the safety distance)I cut mine to .006.

Now see how long your cases are, and I think your bullet will seat better.

In my 30-30 my chamber is .046 bigger than the standard. If I cut my cases to 2.029 like Hornady wants for the FTX I shoot, there would be a .040 gap to cross to the lands. So I lengthened the cases to 2.033, and my OAL to 2.590 from 2.550.

This closed the gap, and maintained the ogive on the case for maxinum coefficient.

[WILCO]

Check this out:

http://www.surplusrifle.com/shooting/castfiller/index.asp

[zomby woof]

My COL for that boolit is 1.610".

[jasperman]

thanks, Zomby Woof. So at 1.610, where is the case mouth on the bullet? Do you have an exposed lube groove?

[zomby woof]

The round on the left is 1.610". The round on the right is modified so I can insert this into the chamber and through the flash hole push the boolit until it hits the rifling. Then measure the COL and back it off a ways. My rifle was hitting about 1.620" with this boolit. They shoot good.

http://www.hunt101.com/data/500/medium/100_2498.JPG

[Lead Fred]

:holysheep:holysheep:holysheep:holysheep:holysheep :holysheep:holysheep

How about one fo these. I bet you might get a wee better meaurement

(get the bent on for a semi-auto)

http://www.cabelas.com/cabelas/en/templates/links/link.jsp?id=0044519216354a&type=product&cmCat=SEARCH_all&returnPage=search-results1.jsp&Ntt=oal+gauge&Ntk=Products&sort=all&_D%3AhasJS=+&N=0&_D%3Asort=+&Nty=1&hasJS=true&_DARGS=%2Fcabelas%2Fen%2Fcommon%2Fsearch%2Fsearch-box.jsp.form1&_dyncharset=ISO-8859-1

you may have to look for a 30 case or tap one of yours out to fit the above gizmo

http://www.cabelas.com/cabelas/en/templates/links/link.jsp?id=0044519216353a&type=product&cmCat=SEARCH_all&returnPage=search-results1.jsp&Ntt=oal+gauge&Ntk=Products&sort=all&_D%3AhasJS=+&N=0&_D%3Asort=+&Nty=1&hasJS=true&_DARGS=%2Fcabelas%2Fen%2Fcommon%2Fsearch%2Fsearch-box.jsp.form1&_dyncharset=ISO-8859-1

[22lover]

Zomby - I don't notice any "bulge" on your brass from the seated boolit. Did you use a factory crimp die? I'm having mucho trouble getting the Lee 120 seated without crimping the case lip into the lube groove. Seems like I have to seat to about 1.58 or so such that it's not a problem, which is 0.1" shorter than the recommended min OAL.

Thanks,

Bill

[Le Loup Solitaire]

Hi, I wrote a bit on another thread regarding this problem. Bullets that seat or are being seated should not cause/make bulges. The most common cause of this is a bullet that is oversize as cast or else not sized enough/to the correct diameter. On OAL...the overall length on the carbine is not critical. The limiting factor is primarily the length allowed by the magazine. Too long= you can't get them in the mag or else the noses are rubbing on the the fronts. Shorter will go in the mag and feed as they are supposed to. Making the rounds too short means that the bullets have to be seated deeper...this cuts down on the powder space and it can and usually does raise the pressure a bit. The solution to this is to reduce the powder amount...but not to the point of getting innacurate shooting. If that occurs then you have to try/use a different powder. I had to do this in loading for a Ruger Blackhawk where any amount of front band projecting beyond the mouth of the case would make the round too long and the case sticking out in back of the cylinder wouldn't let it rotate. I had to seat the entire length of the band into the case and that was a lot of seating depth. From my experience with using deep seated wadcutters in the 38 special I knew that the powder charge would have to be reduced and thats what I did. In the carbine rifle I wanted to use 14 grains of 4227 and it simply wouldn't fit/allow the bullet to go in deep enough so I reduced the charge to 13.5 and then it worked. 0.1 shorter or even a bit more is not a critical amount in the 30 carb on the OAL, but keep an eye on the grouping which is where changing anything variable can and usually does show up. LLS

[zomby woof]

I use a LEE case expander, then seat the bullet and just kiss the brass with a LEE FCD. Boolits are sized to .309".