What bushing size are you guys using to get .001-.002 neck tension for 223 lapua brass?
Planning on using 75 grain BTHP or ELD.
Planning on using 75 grain BTHP or ELD.
Bushing Size For 223 Lapua Brass
- Thread starter Dbinford12
- Start date
I chose a .247, then expand .002 via turning mandrel. My loaded round with lapua and 75 eld measures .251
On the micrometer 223 lapua is from .013-.014 thick depending on which side of the neck you measure.
On the micrometer 223 lapua is from .013-.014 thick depending on which side of the neck you measure.
I’m not familiar with a turning mandrel, does this change the thickness of the neck?
Just wondering if the loaded round dimensions are smaller cause I’d neck turning I guess.
I will just be using standard bushing dies.
Yes, if you were turning your necks that would change the thickness but mandreling doesn’t necessitate applying the cutting blade to the brass, just an expansion step.
A turning mandrel is a separate second die set up to expand the neck to its final inside diameter (or used for neck turning in its original application). I use that instead of an expander ball that comes in the bushing die.
If you leave the expander ball installed into the die it achieves the same thing, expands the neck to an inside diameter of ~.002 under bullet diameter. The mandrel should provide even more consistent results is the theory.
A turning mandrel is a separate second die set up to expand the neck to its final inside diameter (or used for neck turning in its original application). I use that instead of an expander ball that comes in the bushing die.
If you leave the expander ball installed into the die it achieves the same thing, expands the neck to an inside diameter of ~.002 under bullet diameter. The mandrel should provide even more consistent results is the theory.
Thanks for info. So if a loaded round is .251 a .250 or .249 bushing should work for the neck tension I’d like to accomplish?
Looking for .001-.002 tension to run in abolt gun.
If you dont want to do any expansion of your case necks then yes, a .250 bushing would provide .001" of tension/interference fit/bullet grip. A .249 would provide .002 if you remove the expander ball from the die.
Just have to be aware of brass spring back, a .250 may actually leave necks .251 so it wouldnt be enough hold and a .249 bushing may actually leave them at .250 for less than you would have figured. If your chamber allows for them to grow large the bushing may not size it down enough to overcome the springback and fail to provide its indicated measurement.
Just have to be aware of brass spring back, a .250 may actually leave necks .251 so it wouldnt be enough hold and a .249 bushing may actually leave them at .250 for less than you would have figured. If your chamber allows for them to grow large the bushing may not size it down enough to overcome the springback and fail to provide its indicated measurement.
Learn something new everyday lol. I didn’t realize you’d need to removed the expanded ball to get more than .001, I haven’t looked but can your remove the expander ball but still leave the decapping pin?
Yes, it thats actually what I do. It should come with the stuff do do just that, leave it just the decapping pin.
I knew the expander ball wasn’t necessary if using a bushing but didn’t know all the stuff I mentioned before. It’s worked out in my 6.5 Creed with hornady brass to just subtract .001 from loaded round to give me about .0015 neck tension. Will have to keep an eye out for that if minus .001 isn’t giving me enough tension. Thanks for all the info man I really appreciate it.
I may also consider looking at a mandrel. Might be interesting to play around with.
So if I want to use an expander mandrel to get .001 neck tension I would run the case through my sizing die with a bushing die something like .003 smaller than the loaded round (with expander ball removed), and then run it through an expander mandrel die to set the final neck tension to .001?
Correct.
Expanding mandrels are .001 less than bullet diameter, Turning "Arbors" as 21st century calls them are .002 less.
This mandrel
http://www.xxicsi.com/arbors-and-mandrels.html
Can go inside this die body
http://www.xxicsi.com/expander-die-body.html
Like so. Then as you raise the brass up into the die on the press the case mouth is forced over the arbor which should keep it perfectly straight up and down and concentric on the inside diameter.
In order for the mandrel to do anything it has to be able to work on smaller brass. If the neck isnt sized down far enough then it cant do anything. to work it.
Interesting thanks a ton for the advice. How much difference have you noticed in performance of ammo when doing this?
I’m a PRS shooter fairly new to reloading so learning new stuff everyday at this point.
How much? Not really an appreciable amount
I thought I had a test somewhere that I did them side by side but I cant find the pics now. My take away was that it was slightly better, maybe 3" at 500 instead of 4" but there is enough going on that it very well could have just been happenstance. A much bigger test would be needed to be conclusive.
I will do it for my precision 223 and 6xc since I already bought all the stuff to and have nothing better to do with my time.
For hunting rifles, ars, plinkers etc Im not going to bother with handling each piece of brass twice to size it.
I will size all of my virgin brass over it to at least set the tension on those close to one another, hoping for more consistent fired case dimensions as a result, makes me feel better.
You will notice a distinct difference when seating bullets. If the bullet does not seat easily with .001 - .002 tension then your brass needs to be annealed.
I, like spife7980, use a .247 bushing with the expander mandrel. I expect to have .001-.0015 neck tension when all is said and done.
Also, it is very very important to to large lots of brass at one time. Keep that lot together. If I have 400 pieces of Lapua brass, I like to ensure that I process 200 at a time minimum (where possible). For example, if I do 200 pieces of brass, they stay together until they are shot.
I, like spife7980, use a .247 bushing with the expander mandrel. I expect to have .001-.0015 neck tension when all is said and done.
Also, it is very very important to to large lots of brass at one time. Keep that lot together. If I have 400 pieces of Lapua brass, I like to ensure that I process 200 at a time minimum (where possible). For example, if I do 200 pieces of brass, they stay together until they are shot.
I'm using the Brownells/Sinclair expander mandrill and die body with either 0.247 or 0.248 bushing. With virgin lapua brass the last two lots I've gotten the neck tension was so tight I ended up running each piece through the expander die three times. It's a very useful tool for under $50, definitely gran one.
Redding 249 bushing for my Lapua brass with the expander ball removed from the die. 244 for all of my misc range pick up brass.
Hornady 75 gr BTHP can be seated to magszine length, the ELD-M cannot. If you are single feeding you can get away with less neck tension.
They can’t be seated to AR mag length no but I’ve run many a 75 ELD in a 223 bolt gun and getting ready to run some 80s maybe even 85.5s in MDT mags.
Do hornady, redding, or whidden publish the equivalent bushing size for the necks of their standard, non-match/bushing sizing dies?
