headspacing (again)

i have read lots of threads on here about this, and thought i was doing it the best way possible, but ran into a glitch. On the advice that i gleaned on here i decided that go/no go gauges were the way to do my headspacing so i bought them. i have a heavy barreled .308 that shoots the legs off of flies and i wanted a smaller lighter counterpart that shot the same reload that i use. so the new one i set up with the go/no go gauges. the go goes. the no go just barely no goes. if i chamber one of my pet loads the bullet is pressed into the shell as the bolt closes(which requires quite a bit of pressure)
on my other gun i worked up that load to have the bullet sit maybe 1 or 2 1000ths off the lands. on this one it is obviously way past the beginning of the rifling. my question… can i headspace the new barrel to my ammo? can i load up a dummy round with no powder or primer to overall length, then set barrel 1/1000th off the bullet like my other savage?
can the chambers be so far off as to make that not safe?


if so, i might just try compressing each round as i chamber it. i don't want to have to have two separate .308 loads, and the one i shoot now has developed over years. i will not change it.

any advice/suggestions?

tim

You are not dealing with a headspace issue, you are dealing with two different throat lengths. Changing headspace to achieve proper bullet distance from the lands may prove to be very dangerous.

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Originally Posted by acmetim

i don't want to have to have two separate .308 loads, and the one i shoot now has developed over years. i will not change it.

any advice/suggestions?

tim

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I wouldn't expect that to work well, although you may luck out. Headspace and throat length are two entirely separate things. You could have the new chamber re-cut with the same reamer as the first then set headspace the same so they are dimensionally alike, but every barrel is different when it comes to loads.

dang it. i was afraid id get some sensible advice…. i guess i assumed that the chambers would be more or less the same. now i can probably assume that my accuracy load for my model 10 will likely not work well in many .308's. i did fire it the once. i figured i had already set the bullet deeper….give it a shot. it fired fine. but i wasn't anxious to do it again. color coded brass. i guess i need that now…. or make the .308 into a 223….

i wasn't expecting the same accuracy. minute of deer would have been fine. it was a lightweight 16" bbl. i do some long hunts in the mountains and my model 10 weighs near 9 lbs i'd guess. sometimes the laurel is so thick i am literally crawling. no shots up there past 100 yds most times. less than 50 and fast is more usual.

how dangerous is it to seat the bullet in the brass just a little deeper each time i close the bolt. id say the compressed one was about 1/16 shorter after i closed the bolt on it. still plenty of room till the powder.

Why not just throat the 2nd barrel so they are the same ?

You have a few choices. Work up a new load for the new gun, using a bullet that won't be easy to confuse with your original load. Try seating the bullets deeper and see if it has any adverse effects on the original rifle. Rebarrel to a different chambering. Or have the new barrel rethroated to match the other one. I would choose the last one myself.

I will look into rethroating. I once cut a chamber for a .22 barrel I built. I doubt it's much different...? I assume there is a piloted reamer I could find?

If it were my choice to make, before re-throating the second rifle, I would work up a load for the second rifle that would also work in the first rifle. You may find out that the two chambers are different enough that they need to be considered as two totally different entities. The only way to have a chance of two separate 308's performing the same with the same loads, is if the chambers were both cut with the same reamer, and yours apparently were not. To a large extent, each chamber is an entity unto itself, but if you load to the second rifle, you may still get acceptable "hunting" accuracy from the first rifle, but may give up some of your original accuracy.

Hope this helps?.......Jim ;-))