I need information on how far to seat the Bullet from the rifling lands in .308

Boneyard · August 18, 2000, 05:25 PM

I'm loading .308, 150 grain Spitzer ballistic tip nosler bullets for a Savage FP10 bolt action with 1/9" twist, 24" heavy barrel.....I was reading somewhere that you could seat a bullet real long (no powder or primer) and then close the bolt on it and then it would seat the bullet to the depth of the rifling lands....and then to seat your bullets .015 to.030 deeper....the sierra loading manual says c.o.l. for this round should be 2.770"..when I tried this procedeure the c.o.l. was 2.926..this seems awful long to me..do any of you experienced riflemen have any advice for me on this?..would'nt that change chamber pressures?..I have been reloading pistol for about 3 years but I am just beginning to load Rifle rounds so I want to get the best possible accuracy from my rifle.
Any help would be greatly appreciated..
Thanks

Watchman · August 19, 2000, 11:11 AM

Most benchrest shooters use the longest loaded bullet they can fit in the rifle. The usual limitation is the magazine, as some bullets would be too long to put in your magazine,thus turning your bolt action into a single shot.However , lots of benchrest just load one at a time , so this is not a big deal.

The only change in the chamber pressure would be if you actually seated the bullets ON the rifling.

This is where yout best accuracy comes in , when your bullet is seated ON the rifling. Since you will have a spike in pressure, you MUST reduce your powder charge or you WILL get signs of high pressure.

One thing you must watch is that your bullets must be very consistent in overall lenth. If they vary more than a couple of thousanths, you could have problems. If you JAM a cartride in your rifle that is longer than the rest,and you hunt all day without firing a shot , you may pull the bullet right out of the case when you are extracting it. Then you have gunpowder all over the place. Generally, you only want to load on the rifling for targets. For hunting , .010 off the rifling would be best to avoid any problems.

Also, if long loading to the rifling , it would be a good idea to chronograph your loads. It may be that when you reduce your loads, you may still get exellent velocity as the added pressure that it takes to move the bullet upon firing will speed things up a bit. It will also be a more consistent load, and consistency is the key to good groups from the bench.

Hope this helps.

ol blue · August 19, 2000, 02:17 PM

One thing that I have noticed is that some bullets seem to like it further off the lands. In my M70 Win in .308, the Hornady spire points work good @ .025 off lands, but they work even better @ .050 off lands. So if you have a rifle that has a long throat you might want to experiment with bullets that seem to like it that way. As others have said, if this is for hunting, the most important thing is that they have suffecient clearance in the magazine...ol blue

Hutch · August 19, 2000, 03:19 PM

My 700VS has such long freebore that I can't seat the Sierra 168gr MK out far enough to touch. Keep in mind you need at LEAST 1/2 caliber, preferably a full caliber (.15 to .3 inches) OF BEARING SURFACE of the bullet in the case mouth for practical shooting.

schlickenmeyer · August 19, 2000, 04:47 PM

I use a Stoney Point OAL gauge. not too expensive, and I can tell with each different bullet the relationship of the ogive of the bullet to the start of the rifling of the barrel. also if you shoot a lot, you can adjust for barrel wear by checking this dimension, and then adjusting your seat depth. It's COOL.

Boneyard · August 20, 2000, 06:16 AM

Thanks guys for the great info,..I loaded some .308 rounds yesterday about .oo6" of the lands (2.920") with 150 gr. Nosler ballistic tip boat tail with 42.2 grains of IMR 4064 and got great accuracy out of them...I actually put three bullets through the same hole at 100 yds...I need to do more testing but it seems to be a good load..any suggestions?...if I could figure out how to make them fit in my magazine now I woould have it made..

schlickenmeyer · August 20, 2000, 12:54 PM

Is'nt the OAL 2.80"? If you are that much longer, that is why. try a compromise length and see what happens, I guess.

Bogie · August 21, 2000, 01:46 PM

What I do:

I generally jam my 6PPC loads into the lands about 0.005". My .22PPC likes about 0.005" out from 'em. I worked up the loads with the bullets jammed.

Neck size your case. DO NOT prime or charge. Seat a bullet long, and buff it real nice with some fine steel wool. Measure it. Write it down (yup). Chamber it, and if it doesn't want to close, seat the bullet a little shorter (measure again, write it down), and try again. Sooner or later your bolt will close hard. Open the bolt, and extract the case. You may have to punch the bullet out from the muzzle. That means you've got it jammed really hard. You may want to start over again with the bullet slightly shorter in the case (measure/write...). When you have it so that the round chambers, showing just barely visible land marks on the buffed bullet, you're there. Push the bullet another 0.001" into the case, and that's your "at the lands" spot. Now, take the top of your Wilson seater hand die, loosen the lockscrew, and screw the seater in. Then, with the dummy round in the die, screw the seater down until it contacts the bullet. Back it out just a hair, and write down the length of the seater top. You'll adjust from there.

You say you don't use a Wilson hand die? I suppose you can struggle through with press mounted dies, but you'll get the best accuracy from the hand dies.

August 18, 2000, 05:25 PM	#1
Boneyard Senior Member Join Date: January 30, 2000 Posts: 158	I'm loading .308, 150 grain Spitzer ballistic tip nosler bullets for a Savage FP10 bolt action with 1/9" twist, 24" heavy barrel.....I was reading somewhere that you could seat a bullet real long (no powder or primer) and then close the bolt on it and then it would seat the bullet to the depth of the rifling lands....and then to seat your bullets .015 to.030 deeper....the sierra loading manual says c.o.l. for this round should be 2.770"..when I tried this procedeure the c.o.l. was 2.926..this seems awful long to me..do any of you experienced riflemen have any advice for me on this?..would'nt that change chamber pressures?..I have been reloading pistol for about 3 years but I am just beginning to load Rifle rounds so I want to get the best possible accuracy from my rifle. Any help would be greatly appreciated.. Thanks

August 19, 2000, 11:11 AM	#2
Watchman Junior member Join Date: August 8, 2000 Location: ARKANSAS Posts: 484	Most benchrest shooters use the longest loaded bullet they can fit in the rifle. The usual limitation is the magazine, as some bullets would be too long to put in your magazine,thus turning your bolt action into a single shot.However , lots of benchrest just load one at a time , so this is not a big deal. The only change in the chamber pressure would be if you actually seated the bullets ON the rifling. This is where yout best accuracy comes in , when your bullet is seated ON the rifling. Since you will have a spike in pressure, you MUST reduce your powder charge or you WILL get signs of high pressure. One thing you must watch is that your bullets must be very consistent in overall lenth. If they vary more than a couple of thousanths, you could have problems. If you JAM a cartride in your rifle that is longer than the rest,and you hunt all day without firing a shot , you may pull the bullet right out of the case when you are extracting it. Then you have gunpowder all over the place. Generally, you only want to load on the rifling for targets. For hunting , .010 off the rifling would be best to avoid any problems. Also, if long loading to the rifling , it would be a good idea to chronograph your loads. It may be that when you reduce your loads, you may still get exellent velocity as the added pressure that it takes to move the bullet upon firing will speed things up a bit. It will also be a more consistent load, and consistency is the key to good groups from the bench. Hope this helps.

August 19, 2000, 02:17 PM	#3
ol blue Member Join Date: January 21, 2000 Location: USA Posts: 62	One thing that I have noticed is that some bullets seem to like it further off the lands. In my M70 Win in .308, the Hornady spire points work good @ .025 off lands, but they work even better @ .050 off lands. So if you have a rifle that has a long throat you might want to experiment with bullets that seem to like it that way. As others have said, if this is for hunting, the most important thing is that they have suffecient clearance in the magazine...ol blue

August 19, 2000, 03:19 PM	#4
Hutch Senior Member Join Date: February 12, 2000 Location: Birmingham, AL Posts: 1,124	My 700VS has such long freebore that I can't seat the Sierra 168gr MK out far enough to touch. Keep in mind you need at LEAST 1/2 caliber, preferably a full caliber (.15 to .3 inches) OF BEARING SURFACE of the bullet in the case mouth for practical shooting.

August 19, 2000, 04:47 PM	#5
schlickenmeyer Senior Member Join Date: July 1, 2000 Location: mn Posts: 150	I use a Stoney Point OAL gauge. not too expensive, and I can tell with each different bullet the relationship of the ogive of the bullet to the start of the rifling of the barrel. also if you shoot a lot, you can adjust for barrel wear by checking this dimension, and then adjusting your seat depth. It's COOL.

August 20, 2000, 06:16 AM	#6
Boneyard Senior Member Join Date: January 30, 2000 Posts: 158	Thanks guys for the great info,..I loaded some .308 rounds yesterday about .oo6" of the lands (2.920") with 150 gr. Nosler ballistic tip boat tail with 42.2 grains of IMR 4064 and got great accuracy out of them...I actually put three bullets through the same hole at 100 yds...I need to do more testing but it seems to be a good load..any suggestions?...if I could figure out how to make them fit in my magazine now I woould have it made..

August 20, 2000, 12:54 PM	#7
schlickenmeyer Senior Member Join Date: July 1, 2000 Location: mn Posts: 150	Is'nt the OAL 2.80"? If you are that much longer, that is why. try a compromise length and see what happens, I guess.

August 21, 2000, 01:46 PM	#8
Bogie Senior Member Join Date: June 5, 2000 Location: Job hunting on the road... Posts: 3,827	What I do: I generally jam my 6PPC loads into the lands about 0.005". My .22PPC likes about 0.005" out from 'em. I worked up the loads with the bullets jammed. Neck size your case. DO NOT prime or charge. Seat a bullet long, and buff it real nice with some fine steel wool. Measure it. Write it down (yup). Chamber it, and if it doesn't want to close, seat the bullet a little shorter (measure again, write it down), and try again. Sooner or later your bolt will close hard. Open the bolt, and extract the case. You may have to punch the bullet out from the muzzle. That means you've got it jammed really hard. You may want to start over again with the bullet slightly shorter in the case (measure/write...). When you have it so that the round chambers, showing just barely visible land marks on the buffed bullet, you're there. Push the bullet another 0.001" into the case, and that's your "at the lands" spot. Now, take the top of your Wilson seater hand die, loosen the lockscrew, and screw the seater in. Then, with the dummy round in the die, screw the seater down until it contacts the bullet. Back it out just a hair, and write down the length of the seater top. You'll adjust from there. You say you don't use a Wilson hand die? I suppose you can struggle through with press mounted dies, but you'll get the best accuracy from the hand dies.