69gr SMK

[potatobed409]

I'm reloading for a .223 Rem with the 69gr SMK. The max COAL for my mag is 2.260. By my figuring this will put the ogive of the bullet inside of the case mouth by about .008. Does this seem right or am I missing something.

 

[6BRLongRange]

You're missing something. Where did you get the COAL measurement that you're referring to?

 

[25AI260]

409....
Charlotte ...wow wilmington...

your c.o.a.l., ... tell us what that is ? you must be missing something !!!!

 

[fdshuster]

potatobed409: You did not say what type firearm you are loading the 223 Rem. ctg for. If it is an AR-15 and you want to magazine feed, then yes, they must be a max of 2.260". If you're loading for a bolt action, single-shot, etc. you can seat them to any length you want. Most of us take throat depth measurements and seat the bullet accordingly: could be .020" off the lands, touching, or whatever. If using them in my AR's, they are all single loaded for the slow fire courses of fire that require single-load. And yes, according to a quick check, the ogive is very close to or maybe even slightly below the case mouth, but then, if you are trimming the cases to the suggested 1.750", the problem would be made even worse, since you could be overtrimming the cases. Most of us (again) measure our actual chamber lengths, and trim (or not) according to the actual length of our chambers, not some "one-size-fits-all" dimension.

 

[potatobed409]

I am reloading for a Remington 700. I had the smith true the action and put on a 1 in 8 twist barrel to shoot the heavy bullets. I took a fired case and got the case mouth where I could slide a 69gr SMK in and out fairly easy. Then I chambered the round so I could get a measurement to the lands which is 1.772 to the ogive (used a bullet comparator from sinclair that attaches to the calipers). Then I measured the COAL (Cartridge Over All Length) which was 2.281. The max case length in the manual says 1.760, that only leaves me .012 to seat the bullet before the ogive enters the case mouth and at .012 set back it gives me a COAL of 2.269. I am going to get a AICS stock for the gun, and the max COAL for the magazine is 2.260. Does these figure seem right? I've checked them four times. I've got to be missing something. javascript:void(0);???

 

[gpoldblue]

potatobed409...1.760" case length=trim time. Trim your cases back to 1.750" & you'll pick up .010" right there! However,since you're loading for a Remington 700,you don't have the 2.260" limitation.
I'd load 'em .010" off the "just touching" figure(.010" off works best
in my rifle---Savage M12,LRPV). You may want to start at "jam" & work backwards progressively seating deeper 'til the rifle shoots best. Good luck...good shooting...gpoldblue

 

[fdshuster]

409: Since the rifle you're loading for is a Rem. 700 Short-Action, you really do not have a 2.260" restriction on o.a.l. to feed from the magazine. These magazines are very generous on their lengths, for a "short" ctg. like a 223. If you're Rem 700 is like one of mine, ( chambered in 222 Rem), there is a sheet metal filler at the rear of the magazine that could be removed, but even with it in place, ctgs. longer than 2.260" will feed. Sounds like you may have a fairly short throat in your chamber. My Hart barreled 1-8, cut with my Pacific reamer has .074" of freebore, and my ogive length to touch, with the Sierra 69 gr. #1380 ( one of my most used bullets) is 1.992" with a loaded round o.a.l. of 2.384". These are used with a Savage mdl 10 action. If I were you, I would disregard the 2.260" loading manual length, (it's only a standard they all use, to guarantee they will feed in a AR-15 maqgazine), and seat 'em out to touch, or .010" or .020" off the lands, whatever works best. Factory 223 ammo is all loaded to 2.250" to 2.255" o.a.l., again so they will magazine feed in the popular AR-15, but when reloading we don't have that restriction. A longer post than I intended: if you have any questions or comments, feel free to PM. An added thought: by seating them really deep, at 2.260" you have the base of the bullet well below the body/shoulder junction where it's intruding on an already limited case powder capacity. Seat them further out, to touch, for example, and you will increase your space for much needed powder.

 

[infantrytrophy]

Something is not right. Either your measurement of the COAL of the cartridge with the bullet seated "touching the lands" is wrong, or your chamber is very short.

To give an example for my AR with a Wylde chamber, the COAL for the loaded round with the ogive touching the lands is about 2.450. This is using SMK 80's, but it should be similar with the SMK 69's.

The Wylde chamber is longer than the typical chamber for a bolt-action 223, but your chamber appears to be very short, if your numbers are correct.

Are you sure that the bullet is not moving in the case when you chamber the round to "touch the lands"? Can you reproduce your measurement repeatedly within a couple thousandths or so?

You would think that a barrel with a 1-8 twist (for heavier bullets) would have a long enough chamber so that the heavier bullets (69, 75 or 77 grains) would not be seated too deeply.

Randy

 

[fdshuster]

409: Really suggest you take throat depth measurements with the Stoney Point/ Hornady chamber O.A.L. gauge for an accurate, dependable throat measurement. As mentioned by Randy, your measurements indicate a short throat, which would not be the best with an 8 twist. If the throat is short, it could always be lengthened with a throating reamer to whatever depth you want.

 

[people]

I just got a second upper for my AR I use in service rifle comp. It has a short throat. I mag length load hornady 75gr and 77gr SMK and I love it. I can shoot the same ammo XTC. A 1:8 will stabilize a 80gr bullet easily.

If I had a bolt I would like it a little longer so I could get extra powder in it. There is nothing wrong with a short throat except you limit your powder capacity with some bullets.

 

[distinguished]

To keep this simple, if you are going to use mag feed. Trim your cases to 1.750. If the mags you are using allows 2.260" max length, then, seat your bullets to 2.255" average OAL. I use the term average because of the variation in bullet tips. If you single load, then seat bullets 10-20 thou. off. You can experiment with the jump for single loading to see what gives the best groups.

 

[kentuckytroutbum]

To keep this simple, if you are going to use mag feed. Trim your cases to 1.750. If the mags you are using allows 2.260" max length, then, seat your bullets to 2.255" average OAL. I use the term average because of the variation in bullet tips. If you single load, then seat bullets 10-20 thou. off. You can experiment with the jump for single loading to see what gives the best groups.

That's the way I do it! ;D

 

[potatobed409]

I've measured four times and got all the same numbers within about .002, so I'm confident that the measurement is correct. I think I can get buy with the 69gr SMK but I wanted to try the 75gr AMAX and maybe the 77gr SMK. I do not think I can with such a short throat. I'll just get some and try. I cant get the 69gr to group well with RE15. I've got to make some changes.

 

[Ackman]

1)...1.760" case length=trim time.
2)Trim your cases back to 1.750" & you'll pick up .010" right there!

Not true.
1) A 1.760" case isn't too long. It doesn't need trimming. A .223 chamber will be at least .020" longer than those cases as they are.

2) Trimming .010" only adds that amount to the free space between end of case and end of chamber. Like adding .010" freebore, only worse.

 

[Ackman]

I don't load 69's in the 223, but with factory 22-250's and 55's I've seen the casemouth well past the ogive. If that's how it comes out with your rifle, shoot it that way. Bullet to lands relationship is all you really need be concerned about.

Don't worry about COAL. Inside chamfer and necksize a new case then split the neck with a dremel cutoff wheel. Take that cut all the way down and just into the shoulder. Put a bullet in the neck and chamber the whole thing. Then use the Davidson ogive gauge. That's your measurement touching the lands and it's the only one you need worry about with a Remington magazine. Do it a few times til you know the read is consistent. Adjust neck tension by squeezing. The whole thing is simple and quick and cheap and it works.

 

[rfair]

Hodgedon says the 223 with a 69 MK oal should be 2.235!

 

[25AI260]

409.. there is a lot of great info posted you should have hit on something by now.. i wonder though are you subtracting the 1 " for bullet comparator ?
Anyways... lets try this an lets see how it works out for your .. make up a dummy round with your 69smk.. no primer/powder measure without the bullet comparator the oal of the bullet... then measure the oal of the case an add the numbers up... from that total subtract .285, set your seating die to that number measuring with your dail caliper... then try an chamber the bullet... if its real tight come down .005 at a time till it feels good to you...
let us know what coal you come up with

powder/what works in my 700 P 26" hb 1~9tw .. try W 748/24.8 or Varget/ 25.3 for better accuracy then the Re- your using... .... i trim most of my cases to 1.755-8 .. i wouldn't Not trim new case leaving new cases untrimmed at 1.760 can coause trouble
hope this will help..