I did a search, but did not find a definitive answer. I am having a .260 built right now, and as we all know, .260 brass is a little hard to come by. I have a boat load of 1x .308 brass, and wondered what the consensus is on forming the .260 from it? I would think that I could run it through a 7mm-08 sizer, then through the .260 sizer and be good to go. What are the pros and cons to doing this?
Forming .260 brass from .308
- Thread starter nso123
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Re: Forming .260 brass from .308
Aside from working the neck brass, you would be better to start from 7mm-08 than 308, as you would likely have to ream the neck out if you went from 308 to 260. Don't plan on it giving great results or lasting past 4 reloads unless you have it annealed after reaming the neck. If you do go from 308 to 260, remove the expander ball as you move down, or substitute a small expander, such as a 260 in the 7mm-08 die. Plan on buying a Forester inside the neck reamer.
Aside from working the neck brass, you would be better to start from 7mm-08 than 308, as you would likely have to ream the neck out if you went from 308 to 260. Don't plan on it giving great results or lasting past 4 reloads unless you have it annealed after reaming the neck. If you do go from 308 to 260, remove the expander ball as you move down, or substitute a small expander, such as a 260 in the 7mm-08 die. Plan on buying a Forester inside the neck reamer.
Re: Forming .260 brass from .308
I have responded to the same question about necking 308 brass to 260 brass many times.
I will try to answer differently.
A) This 2003 pic of mine from necking down 308 to 243 in three cases, all with the same load, shows the pressure variations possible with some necks pinching more than others.
B) In 2012 I necked down Lapua small primer 308 brass to 260 so I could shoot very high pressures and not get loose primer pockets.
All of those necks, I had to turn.
I used the Bryant method in the lathe.
http://www.bryantcustom.com/articles/neckturn.htm
I have responded to the same question about necking 308 brass to 260 brass many times.
I will try to answer differently.
A) This 2003 pic of mine from necking down 308 to 243 in three cases, all with the same load, shows the pressure variations possible with some necks pinching more than others.
B) In 2012 I necked down Lapua small primer 308 brass to 260 so I could shoot very high pressures and not get loose primer pockets.
All of those necks, I had to turn.
I used the Bryant method in the lathe.
http://www.bryantcustom.com/articles/neckturn.htm
Re: Forming .260 brass from .308
Some places are getting a few items back in stock, I just saw Powder Valley has a quite a bit of Lapua brass in stock.
Some places are getting a few items back in stock, I just saw Powder Valley has a quite a bit of Lapua brass in stock.
Re: Forming .260 brass from .308
I agree with forming from 7-08.. I've made quite a bit of 260 from it and had no issues.
Gary
I agree with forming from 7-08.. I've made quite a bit of 260 from it and had no issues.
Gary
Re: Forming .260 brass from .308
I think the short answer to the 308-->260 brass forming question, is that it comes down to the chambers neck diameter.
Measure a piece of legit 260 brass (neck diameter) fired in your chamber. Subtract .0015" from that. This is, or very nearly is, your chambers neck diameter.
As long as your LOADED 308-->260 neck diameter is at least .002" smaller than the calculated neck diameter of the chamber, it's OK.
As mentioned above, be mindful of neck wall thickness variations in your brass, as you can run into issues awful fast.
As far as I'm concerned, the shorter length of 308 brass as compared to 243, 260 and 708 brass is a non issue. So what if there's .030" more chamber neck ahead of the case mouth? People routinely trim 308 brass to 2.000", and most typical factory 308 chambers will accommodate 2.040" or more. Doesn't hurt anything...
...with the caveat that it may get fouled in that dead zone, and should be cleaned prior to using longer brass, to avoid neck clearance issues.
I think the short answer to the 308-->260 brass forming question, is that it comes down to the chambers neck diameter.
Measure a piece of legit 260 brass (neck diameter) fired in your chamber. Subtract .0015" from that. This is, or very nearly is, your chambers neck diameter.
As long as your LOADED 308-->260 neck diameter is at least .002" smaller than the calculated neck diameter of the chamber, it's OK.
As mentioned above, be mindful of neck wall thickness variations in your brass, as you can run into issues awful fast.
As far as I'm concerned, the shorter length of 308 brass as compared to 243, 260 and 708 brass is a non issue. So what if there's .030" more chamber neck ahead of the case mouth? People routinely trim 308 brass to 2.000", and most typical factory 308 chambers will accommodate 2.040" or more. Doesn't hurt anything...
...with the caveat that it may get fouled in that dead zone, and should be cleaned prior to using longer brass, to avoid neck clearance issues.
Re: Forming .260 brass from .308
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GarySpradley</div><div class="ubbcode-body">I agree with forming from 7-08.. I've made quite a bit of 260 from it and had no issues.
Gary </div></div>
Me too. Once through the 260 die and it's done. Nothing else required.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GarySpradley</div><div class="ubbcode-body">I agree with forming from 7-08.. I've made quite a bit of 260 from it and had no issues.
Gary </div></div>
Me too. Once through the 260 die and it's done. Nothing else required.
