P.O.ing the 260.
Re: P.O.ing the 260.
Shooters have been sold a bunch of hype about the structural advantage of a small rifle primer without being informed of the metallurgical constraints of brass alloys. Brass yields at 65K psi. Unless you own a Creedmoor. They're special
The reason a small primer pocket lasts longer than a large primer pocket in theory, is the expansion percentage applied to a smaller radius is of course less. So the same amount of crush in either shows less effect in the smaller radius as expansion flow should be uniformally outward in the area of unsupported brass, namely the case head rim, groove and web.
In my 308 comparison the head expansion was similar for LRPs and SRPs, but the SRPs were noticeably firmer to seat.
The reason a small primer pocket lasts longer than a large primer pocket in theory, is the expansion percentage applied to a smaller radius is of course less. So the same amount of crush in either shows less effect in the smaller radius as expansion flow should be uniformally outward in the area of unsupported brass, namely the case head rim, groove and web.
In my 308 comparison the head expansion was similar for LRPs and SRPs, but the SRPs were noticeably firmer to seat.
- trevort
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Re: P.O.ing the 260.
Thanks. Glad I haven’t ordered a bushing yetkickinback wrote:I’m not putting the tungsten carbide contact surfaces of the micrometer on the cutting edges of the reamertrevort wrote:Glen can you work out the neck diameter of your chamber by measuring the reamer out of interest
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Fired cases measure .2985”
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- 50 BMG
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Re: P.O.ing the 260.
Custom dies and all today.
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- trevort
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Re: P.O.ing the 260.
Do you have a logo?
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Re: P.O.ing the 260.
Yes I do but the stencil printer I use only does text.
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- Camel
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Re: P.O.ing the 260.
Nice work. Only just figured out Workhorse mob is you.
- trevort
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Re: P.O.ing the 260.
So the big question now that I have used Kickinback’s full length die to neck down my 308 brass, should neck turn them (assuming there is enough clearance for safety) before or after fireforming?
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- trevort
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Re: P.O.ing the 260.
And you need a bigger packet of crayonsCamel wrote:Nice work. Only just figured out Workhorse mob is you.
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- Camel
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Re: P.O.ing the 260.
Why ?? If someone isnt told something, how are they sposed to know that something ? Must be Irish logic in there somewhere.
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Re: P.O.ing the 260.
Good question Trev, if you are sure you have enough clearance I would fireform first.
Then clean up the necks. I made 6mm SLRs out of 308 and the necks were a bit fat so I turned them before fireing only a skin though just didnt want to make to much pressure.
You could always take a skin before sizing them to 260.
Gary
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Re: P.O.ing the 260.
When I made 7mm-08 brass from 308 Lapua cases, I neck turned before firing to provide clearance on the minimum SAAMI spec chamber. With the 6x47 Lapua, I fire-formed then turned. Both worked, though fire-formed cases are probably a bit easier to turn if you have sufficient clearance to fire them safely.
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Re: P.O.ing the 260.
Yep what Jason said