308WIN, 175SMK's, and a Rem 700ADL Varmint

[ZombieHitman]

Ok, gang, I need a little guidance.
I did the break in on my new 700, and it shot beautifully with a junk scope and junk ammo!
Now, the real fun begins!
In building a load for my rifle, I've researched the load significantly I think, and have been getting educated on the different means of determining the bullet seating depth in relation to the lands in the throat, as well as a number of other things.
I made one of the "redneck" COAL meters out of a piece of spent brass that had been FL sized, and split it halfway down with a hacksaw (filed off the burrs before chambering it), as a gauge with the actual bullet I will be loading for my rifle.
It measured out at 2.934 COAL.
I know that's the actual, as I measured it 3 times, getting the same reading all three times.
Per the Nosler load book, COAL is listed as 2.810 for the same weight bullet with a similar BC as the SMK (Custom Comp vs SMK).
My question is, as I proceed in developing this load, I've read that I should seat the bullet to a wide variety of depths, but haven't yet figured out how the correlation between seating depth off the lands - IE jamming them into the lands or seating back .010-.040 like the VLD recommends...
Sorry if I'm rambling, I'm attempting to float out all the questions in my head to help me figure out the right questions to ask about it.
Any suggestions on seating depth to maximize accuracy?
THanks in advance!
Dave

 

[Senderofan]

Ok, gang, I need a little guidance.
I did the break in on my new 700, and it shot beautifully with a junk scope and junk ammo!
Now, the real fun begins!
In building a load for my rifle, I've researched the load significantly I think, and have been getting educated on the different means of determining the bullet seating depth in relation to the lands in the throat, as well as a number of other things.
I made one of the "redneck" COAL meters out of a piece of spent brass that had been FL sized, and split it halfway down with a hacksaw (filed off the burrs before chambering it), as a gauge with the actual bullet I will be loading for my rifle.
It measured out at 2.934 COAL.
I know that's the actual, as I measured it 3 times, getting the same reading all three times.
Per the Nosler load book, COAL is listed as 2.810 for the same weight bullet with a similar BC as the SMK (Custom Comp vs SMK).
My question is, as I proceed in developing this load, I've read that I should seat the bullet to a wide variety of depths, but haven't yet figured out how the correlation between seating depth off the lands - IE jamming them into the lands or seating back .010-.040 like the VLD recommends...
Sorry if I'm rambling, I'm attempting to float out all the questions in my head to help me figure out the right questions to ask about it.
Any suggestions on seating depth to maximize accuracy?
THanks in advance!
Dave

The COAL length mentioned in the reloading manuals...I believe is to keep the round short enough to be able to load rounds in the magazine and for it to feed properly. My mentors demonstrated the usefullness of going by what chamber dimensions you have...... go by measuring the actual length of the chamber and go from there. It has saved me time and gas running back and forth to the range. I do, however, make sure my brass is trimmed to specs ( Length .) This technique has worked on many different rounds. If you read enough reports...you can figure out if a round "Likes" to be into the lands or likes to "Jump".

I think you'll want to limit the variables when you're just starting out working up a load. I'm completing a load for my new .308. From the get go...I decided to use a certain brand of brass, primers and bullets. My variables, for this load, is powder charge and seating depth. Lucky for me...I seemed to have found the load on my third powder charge change. Next...I want to try a second powder...one that has a lot of "Positive" reports.

Depending on the twist rate of your barrel... 1:12" I think. You might also want to have some 168gr. SMK's to try. I had a Rem. 700 PSS with a 1:12" twist that did really well with 168's but started to open up with 175 and not very well with 180 gr. bullets. My Rem. 700 Milspec did extremely well with 175's but it had a 1:11.25" twist.

Anyway...Good luck. It will be very rewarding to find what load your rifle "Likes." If this is your first time loading...make sure to start off with lighter charges in your reference books and work up slowly....to stay safe.

Wayne

 

[ZombieHitman]

Well, I'm not doing SQUAT until it warms up above 25! It's a "stupid cold" 11 degrees this morning, and that's just plain too cold for me!

 

[Kiwi Nate]

My Remmy barrels are as Wayne suggested, prone to shooting the 168gr bullets a touch better than the heavier stuff. The differences are nothing dramatic though. Basically, the last two barrels tend to shoot best with 150-155 grain bullets at say .4, between .4 and .5 with 168 grain bullets and with 175-190 grain bullets, groups climb up towards .75". Bare in mind, I load the things fast so I am looking for sweet spots at the high end as opposed to 100fps slower / 2 grains less. Thats the other thing, my remmy barrels have always shown great accuracy at low pressure, poor to average accuracy at medium pressure, great accuracy at high pressure and then it falls off again as pressures build to the point where 30-70fps velocity spikes appear.

I seat to the magazine, not the lands. I have actually had loads shoot worse when I try for the usual 20-40 thou jump, mostly beause I am losing bullet to bore concentricity caused by poor alignment of the bullet in the case. My magic seating depth is 71mm (convert to imperial by multiplying by 25.4) for tipped or VLD bullets and 69.5mm for conventional soft points. I work on a lot of .308's and its always the same, whether the load is run through a Tikka, a Remmy, a custom barrel- whatever. Can't say the same for long bullets as I have not tried seating to the lands. Can only imagine that a long bullet will be less prone to suffer alignment problems because even if it is at the lands, a good portion of the shank should be in the case neck. Regardless, this is something you should eyeball yourself. If it looks wrong, it is. The .308 case does have a relatively short neck, worse for guys like me who over trim necks on long range culling ammo.

Just remember, don't get too hung up on the little details, its a .308 and one of its virtues is that it will behave where others won't. Thats why you should always have a .308 on hand (preferably an M700)- one day you will be playing with some high maintainence lovely that is giving you hell and you will think- man I am glad I have that .308. (this goes in contrast with the days you take a 600 yard shot in high winds, miss completely and wish you had your magnum beast on hand, go home and have a reunion where you take back everything you said about it last week LOL).

Load development should not be too difficult, with the 168's, start at 43gr of H4895 and work up to 45 grains watching for pressure signs. Sweet spot will be around 44.5gr. With the 175's, start at 42.5 and work up to 44.5. Sweet spot will be around 43.5-44gr. These are the typical high end loads I use in my rifles and what I find works in client rifles with no shortening of case life. Again, watch for pressure signs, you might have a monday morning or friday afternoon barrel that spits the dummy at start loads, it happens. I assume no responsibility if things go wrong but am happy to take full credit if everything goes well.

Nathan.

 

[ZombieHitman]

Load development should not be too difficult...With the 175's, start at 42.5 and work up to 44.5. Sweet spot will be around 43.5-44gr. These are the typical high end loads I use in my rifles and what I find works in client rifles with no shortening of case life.
Nathan.

Nathan, that's about what I figured for these particulars, and I do have some 168's on hand for another rifle that I was considering trying in this one as well.
Thanks for the scoop!
Dave