Necking down lapua cases
- Thread starter Wils37
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J E Custom
Well-Known Member
No !
The Lapua cases are annealed and size down very easy. I have done this many times and the
only thing that I found was that the Hornady New dimension dies seemed to work the best
when down sizing the necks. I use the Redding bushing dies for loading.
The 308 cases are .020 shorter than the 7/08 overall and the body of the 308 is .039 thousandths
shorter than the body of the 7/08 so when sizing, neck only the front of the neck to a body length
of 1.750 leaving a donut at the base of the neck and it will headspace on this "donut" and fire form
perfectly.
The fact that the 308 cases are .020 thousandths shorter means that you should not have to trim
the case for chamber clearance.
Be sure and check the clearance of a loaded round against a fired case for at least .003 to .004.
clearance (Some thickening may occur.
J E CUSTOM
Fiftydriver
Official LRH Sponsor
Not much more to add to that but always check your case lengths just to be sure. Taking a 30 cal down to 7mm will make the neck length grow some. Probably not enough to be an issue but put your calipers on each case JUST TO MAKE SURE. Cheap and easy insurance!!!
ALso, it will likely not be an issue at all but again, taking a 30 cal down to 7mm will make the neck thickness increase. If your shooting a factory rifle you will likely have no issue at all. If you have a min spec 7mm-08 chamber, there MAY be issues with neck thickness. Start with a reduced load, make sure a formed case chambers easily, fire in a safe location and then make sure that a bullet will slip through the fired case neck easily that shows there is plenty of room between the chamber neck and loaded round neck so that you do not run into pressure spike issues.
Other then that it will work extremely well.
One other thing is that Lapua 308 brass usually is larger at the base then US made brass of the same family. Again, if you have a standard spec chamber you will be fine. If you have a custom chamber that was cut with a reamer made for min spec on US brass, the Lapua brass will be a bit snug and you will get accuracy issues, I have personally witnessed this on a couple 243 AI rifles I built for customers. Since the US made brass is a bit undersized, I had my reamer made for US brass. The owners tried Lapua brass and it was a bit tight in the chamber and accuracy was terrible. Switching back to Win brass and the rifles shot 1/3 moa consistantly compared to 1.5 moa for the Lapua brass.
Just things to keep in mind.
ALso, it will likely not be an issue at all but again, taking a 30 cal down to 7mm will make the neck thickness increase. If your shooting a factory rifle you will likely have no issue at all. If you have a min spec 7mm-08 chamber, there MAY be issues with neck thickness. Start with a reduced load, make sure a formed case chambers easily, fire in a safe location and then make sure that a bullet will slip through the fired case neck easily that shows there is plenty of room between the chamber neck and loaded round neck so that you do not run into pressure spike issues.
Other then that it will work extremely well.
One other thing is that Lapua 308 brass usually is larger at the base then US made brass of the same family. Again, if you have a standard spec chamber you will be fine. If you have a custom chamber that was cut with a reamer made for min spec on US brass, the Lapua brass will be a bit snug and you will get accuracy issues, I have personally witnessed this on a couple 243 AI rifles I built for customers. Since the US made brass is a bit undersized, I had my reamer made for US brass. The owners tried Lapua brass and it was a bit tight in the chamber and accuracy was terrible. Switching back to Win brass and the rifles shot 1/3 moa consistantly compared to 1.5 moa for the Lapua brass.
Just things to keep in mind.
Thanks,
I tried necking down an old Winchester 308 case at a freinds place and we tried it in his tikka and there was no problem but when I got home and put it in my browning x bolt I could not close the bolt. I fixed it by running it through my die. I think the shoulder was to flat but I guess it shows the difference in tolerances between rifle brands.
I tried necking down an old Winchester 308 case at a freinds place and we tried it in his tikka and there was no problem but when I got home and put it in my browning x bolt I could not close the bolt. I fixed it by running it through my die. I think the shoulder was to flat but I guess it shows the difference in tolerances between rifle brands.
Fiftydriver
Official LRH Sponsor
Good lesson here, all rifles can be different, thats why we handload specifically for one firearm with each load development we do, that includes brass set up as well.
ALWAYS check brass in the rifle it will be used in and make sure everything is correct before firing a live round. NEVER force a round into a rifle chamber. GREAT way to gaul a bolt lug or scratch a chamber.
ALWAYS check brass in the rifle it will be used in and make sure everything is correct before firing a live round. NEVER force a round into a rifle chamber. GREAT way to gaul a bolt lug or scratch a chamber.
