Thread: Grouping problem 338LM

The different tech for running moly bullets , is they seem to need more neck tension due to being so slippery , guys just chuck the necl expander in a drill press and use some real fine wet & dry 800-1200 grit & lightly sand the expander , and knock a thou or 2 off the dia , this means you have a slightly smaller expander , and the neck is a little tighter if that makes sense .


Later Chris

Originally Posted by ChrisF

The different tech for running moly bullets , is they seem to need more neck tension due to being so slippery , guys just chuck the necl expander in a drill press and use some real fine wet & dry 800-1200 grit & lightly sand the expander , and knock a thou or 2 off the dia , this means you have a slightly smaller expander , and the neck is a little tighter if that makes sense .


Later Chris

Interesting. Used Moly for years and never had to do much but add more powder to achieve velocity. But use redding bushing dies without the expander to achieve a low runout so that is where I may have not noticed a requirement for more neck tention. Use HBN now and that is a bit more forgiving.

Originally Posted by R93

Interesting. Used Moly for years and never had to do much but add more powder to achieve velocity. But use redding bushing dies without the expander to achieve a low runout so that is where I may have not noticed a requirement for more neck tention. Use HBN now and that is a bit more forgiving.

Curious... Same here, including the type of dies I own. Used moly in various cals since it first came on the scene. Never had an issue with neck tension. Now only use it in a 6.5 Ackley F Class gun and with that I run almost no neck tension and soft seat with 8thou (initial) engagement into rifling.

Originally Posted by zimmer

Curious... Same here, including the type of dies I own. Used moly in various cals since it first came on the scene. Never had an issue with neck tension. Now only use it in a 6.5 Ackley F Class gun and with that I run almost no neck tension and soft seat with 8thou (initial) engagement into rifling.

For what your doing I reckon moly is fine. If your out and about and coat hunting pills it was a pain in the ass whenever moisture was present....(all the time).
HBN takes all that hassle away. Reduces ES and no where near as messy. Definitely not as slippery as moly but.

Kiwi Greg put me onto it ages ago. He has been using it longer and may have more light to shed on it than I.
I just know it is good stuff and I have never had a visable trace of coppering since using it in quality barrels.
Dont even get a patch come out coated in anything but carbon.

Originally Posted by R93

For what your doing I reckon moly is fine. If your out and about and coat hunting pills it was a pain in the ass whenever moisture was present....(all the time).
HBN takes all that hassle away. Reduces ES and no where near as messy. Definitely not as slippery as moly but.

Kiwi Greg put me onto it ages ago. He has been using it longer and may have more light to shed on it than I.
I just know it is good stuff and I have never had a visable trace of coppering since using it in quality barrels.
Dont even get a patch come out coated in anything but carbon.

Yep any moisture anywhere + moly = corrosion

I don't know how much good HBN does, I have been using it for years, after hurting barrels with Moly.
I clean bugger all & once the rifle has settled down basically no copper fouling is evident even after 100-200+ rounds depending on calibre.
I don't really notice any carbon build up, although I don't have a bore scope yet, but don't know if I want one........
I have noticed that I have quite a few rifles now with silly single digit ES (more often that not), especially with mucking around with neck tension.
I haven't read or seen anything bad about HBN so I will keep coating all the pills for my own rifles, I'm careful not to use coated pills for customers rifles.
I haven't done enough testing yet to see how much difference it makes yet but will grab a nice consistent rifle & load to try with & without HBN.

Originally Posted by Kiwi Greg

Yep any moisture anywhere + moly = corrosion

I don't know how much good HBN does, I have been using it for years, after hurting barrels with Moly.
I clean bugger all & once the rifle has settled down basically no copper fouling is evident even after 100-200+ rounds depending on calibre.
I don't really notice any carbon build up, although I don't have a bore scope yet, but don't know if I want one........
I have noticed that I have quite a few rifles now with silly single digit ES (more often that not), especially with mucking around with neck tension.
I haven't read or seen anything bad about HBN so I will keep coating all the pills for my own rifles, I'm careful not to use coated pills for customers rifles.
I haven't done enough testing yet to see how much difference it makes yet but will grab a nice consistent rifle & load to try with & without HBN.

This is all off topic but here goes -
I am still not sure of the merits of coating although in the case of HBN the great David Tubb cannot be wrong (can he??..??).
I toyed with the idea of changing to Danzac when it came along and ditto for HBN but basically when my 6.5 is eventually toast I will cease using coated projectiles altogether.
I am firing non coated in other target rifles and not having Cu problems.
The reason I went into moly with the 6.5 Ackley was more to test the point that the cartridge would have a barrel life exceeding the 6.5/284's . So I use moly (which won't stop throat erosion I guess) and Win 760 powder because of its lower flame temperature.