308 COL and Lands

[gwagner]

I am loading some .308 with mixed headstamps and 168 Hornady A-max...42.5 gr of IMR 4895 in a Remington 700 SPS Varmint.

At 2.800 COL, the bolt is harder to lock, and the bullets appear as though they are against the lands after I load it and then eject it.

How can I tell what COL gives me the correct distance off the lands? How much further can I seat and should I reduce the charge if I seat slightly deeper?

Thanks,

Galen
Alabama

 

[JDGray]

First off, Welcome to THR!

Sounds like you need to bump the shoulder back on your cases. To find the lands in your rifle, its pretty easy.

1. slowly neck size a fired case so it will just hold the 168gr A-Max, and you can push it in by hand. (Don't crimp it down all the way, or the bullet wont start, and push in easily)

2. Chamber your dummy round, seating the bullet with your bolt.

3. Remove, and measure, subtract .010"-.020", and use this measurement as your max OAL. for the 168gr A-Max. You'll have to do the same measurement for each kind of bullet.

First you gotta get your cases to chamber. To rule out bullets in the lands, try chambering a sized case only, if it won't go, you'll need to lower your sizing die in your press untill they fit

If the bullets are into the lands at 2.800", try seating them deeper by .010" and try again.

 

[USSR]

Galen,

I can almost guarantee you that the bullet being up against the lands is not the reason for your bolt being hard to lock down. Remington's are extremely long throated, and there's no way you are reaching it with a cartridge OAL of 2.800". What is happening is, you haven't FL sized your brass enough. You need to turn the FL sizing die down a "titch" more. Your shoulder is too far out, and that is what is causing the hard to chamber condition.

Don

 

[NCsmitty]

Welcome to THR, gwagner.

I do not believe your COAL is the problem. 2.800 is the usual dimension, and shouldn't be a problem in a Remington. They usually have a long leade to the rifling.
IMO, you cannot make an accuracy load using mixed headstamped cases. More than likely you need to set the sizing die down a bit more to set the shoulder back more. Try doing that and check the empty brass in your rifle first.
Use marker dye or soot on the bullet to see if you are actually touching the lands.
I'm sure others will chime in here.



NCsmitty

 

[gwagner]

Thanks

Thanks guys. I aught to say, it is not HARD to lock, just slightly harder than on factory ammo. I think the ones that are a little harder are LC cases fired once from an M1.

I try some of the empty cases, and adjust the sizing die and report back.

 

[fguffey]

gwagner, I am a big fan of the jump start, back the bullet off of the lands and let it have a running start before it hits the lands, I have never liked the ideal the pressure has to build before the bullet can move to overcome the resistance of being sized, it is a time thing, if pressure builds faster than the bullet can get out of the way pressure can become a problem.

Knowing where the lands are located in relation to the bullet contact does not require a large cash out lay, there are tools that are available and nice to have, I would suggest drilling the flash hole in 10 cases to a diameter that would accommodate a cleaning rod or small wood dowel, in one of the cases I would suggest seating a bullet that you are using to develop loads for, after seating the bullet, remove the bolt of the rifle, chamber the first test case and use the cleaning rod or wood dowel to push the bullet out of the case until it contacts the lands, remove the test case and measure the case over all length (not the best ideal), after determining the location of the lands for that particular bullet install the test case in the seater die and raise the ram with the seater die and seater plug backed out, first lower the seater die with the seater plug raise to avoid contact with the bullet, once the crimp portion of the die contacts the mouth of the case back the die out 1/2 turn (about .034 thousands and secure the die with the lock nut, THEN lower the seater plug until it contacts the bullet, that setting is 'maximum overall length' for that bullet'.

The seater plug protrusion from the top of the die can be used in combination with a dial caliber to set the bullet seating depth. When the seater plug contacts the bullet the index is .000 off the lands, lowering the seater plug .020 will seat the bullet .020 thousands off of the lands.

The case was shoved forward when the bullet was pushed out of the case to make contact with the lands, this means head space was not taken in consideration, in the perfect world the .020 would be plus .005 when the .005 represents a go-gage size chamber and the case is full length sized.

Drilling 10 cases: After seating a bullet in the test case save it for a transfer/standard for that bullet when developing loads and setting up the seater die,, when you start to develop another load for a different bullet assemble another case with bullet.

F. Guffey

 

[Ridgerunner665]

USSR's post is spot on...Remington throats are waaaaay longer than they need to be.

Provided your barrel is not a factory screw up of some sort...there is NO WAY your rounds are touching the lands.

I load mine to 2.82" (as long as will fit in the mag and feed), and I'm still a full .125" (1/8th of an inch) off the lands in all 3 of my Remington 308's.

 

[JDGray]

...Remington throats are waaaaay longer than they need to be.

My newer Rem 700 SPS in .223, has a rather short leade, maybe they fixed there deep throat issue

 

[Ridgerunner665]

My newer Rem 700 SPS in .223, has a rather short leade, maybe they fixed there deep throat issue

Not likely...I just bought my SPS Tactical 308 last year about this time...its got a throat like a giraffe.

Remington and Weatherby have always been that way...likely always will be.

 

[JDGray]

Not likely...I just bought my SPS Tactical 308 last year about this time...its got a throat like a giraffe.

I must of got lucky! I loaded up some 50gr V-Max bullets, and started way longer than the 2.250" OAL that I usually seat at, and ended up right back at 2.250"

At least the long throated Remmy's will still shoot great groups, after you tinker with the OAL!

 

[jbkebert]

I just did some checking a 168 a-max factory round from Hornady measures 2.735 COAL. I am loading mine to 2.908 in a T/C Encore so I don't know about a 700 SPS throat. Mine are seated at .015 off the lands. I could not think that the throat of a factory rifle would only be .065 longer than a factory round. I would agree that you need to bump your shoulder back just a hair at a time until they chamber easier. I tried loading some rounds for my remmy cdl in .260 just off of the lands. They were so long that they could not feed through the mag of the rifle.

 

[Ridgerunner665]

At least the long throated Remmy's will still shoot great groups

They do...usually.

 

[JDGray]

I could not think that the throat of a factory rifle would only be .065 longer than a factory round.

After testing the throat on my factory Savage 10FP, using 168gr SMKs, I was very pleased to find that 2.800" was only .013 off the lands. Factory Fed GMM measured out at 2.805, and shot very well in the Savage, at .008 off.

 

[gwagner]

Thanks guys for all the input.

I took all of the loaded rounds, and the only ones that were hard to chamber were Lake City cases. I turned the sizing die down just a hair more, and the LC empty cases chambered fine.

Now the question...I began pulling the bullets (impact puller) on the 30 or so that are hard to chamber. Can I remove the decapping rod on my RCDB full length die, and run the cases back through primed, or do I have to decap the good primers?

Thanks again!

 

[interlock]

no. just take the de priming pin out, it will be fine

 

[NCsmitty]

Can I remove the decapping rod on my RCDB full length die,

You might be able to move it up enough to prevent decapping, but when FL sizing the case neck, the expander ball gives you the final diameter for your bullet when withdrawing the case from the die.



NCsmitty

 

[USSR]

Too bad you don't have a Redding body die. You could have bumped the shoulder back without removing the bullet.

Don

 

[gwagner]

Ahhh...gotcha. I may just remove the decapping pin.

 

[USSR]

I may just remove the decapping pin.

I would suggest after you remove the decapping pin, and run the brass thru to bump the shoulder back, that you reinsert the decapping pin, and then run the brass thru it only far enough so that the expander ball goes thru the neck, and then pull it out. If you don't do this, you will have excessive neck tension on your brass.

Don