Tight-neck brass thickness - TARGET PICS UP
- Thread starter racesnake
- Start date
Re: Tight-neck brass thickness
0.004" is about minimum for a gas gun, and fine for a hunting / casual shooter, maybe for competition bolt gun too if everything else is done well.
I've found my 6's work best with just 0.011" - 0.012" neck wall thickness so I might be working with 0.005" or more yet I can still shoot X's at 600 & 1k if I do what I ought to every time.
You'll know once you start putting rounds down range whether your work is satisfactory. What's your intended use and with what bullet(s)? Keep us informed please about what you see on target.
0.004" is about minimum for a gas gun, and fine for a hunting / casual shooter, maybe for competition bolt gun too if everything else is done well.
I've found my 6's work best with just 0.011" - 0.012" neck wall thickness so I might be working with 0.005" or more yet I can still shoot X's at 600 & 1k if I do what I ought to every time.
You'll know once you start putting rounds down range whether your work is satisfactory. What's your intended use and with what bullet(s)? Keep us informed please about what you see on target.
Re: Tight-neck brass thickness
If its a no turn neck,then you really dont need to turn your necks but a mere dusting of the neck to true it.You dont have to make it completely clean but about 70-80 percent clean is good enough.With a .272 neck using new brass you should be able to just do the cleanup to get the high spots unless you are forming 6xc from some other cartridge,then it may thicken the necks slightly during the forming operation.I have a .272 neck gun and I have more room now with the new blue box brass that I dont even clean them up.
If its a no turn neck,then you really dont need to turn your necks but a mere dusting of the neck to true it.You dont have to make it completely clean but about 70-80 percent clean is good enough.With a .272 neck using new brass you should be able to just do the cleanup to get the high spots unless you are forming 6xc from some other cartridge,then it may thicken the necks slightly during the forming operation.I have a .272 neck gun and I have more room now with the new blue box brass that I dont even clean them up.
Re: Tight-neck brass thickness
Don't know about long bullet shooters, but in the short range benchrest game, there has been a trend, among some top shooters to increase total neck clearance to somewhere around .003 (.0015 per side), or a little less. I have tried this, and it seems to work, but if I were ordering a new reamer, I would spec, the neck a couple of thousandths larger to make up for the lost brass, and a little more. Brass that is around .008 is a little thin. My current chamber neck diameter is .062. My next action will have a spring plunger ejector and IMO a thicker neck will take the hit better. I have heard that .30 cal. 1,000 shooters can get better results with a clearance of .005 (I think that is the number.)
Don't know about long bullet shooters, but in the short range benchrest game, there has been a trend, among some top shooters to increase total neck clearance to somewhere around .003 (.0015 per side), or a little less. I have tried this, and it seems to work, but if I were ordering a new reamer, I would spec, the neck a couple of thousandths larger to make up for the lost brass, and a little more. Brass that is around .008 is a little thin. My current chamber neck diameter is .062. My next action will have a spring plunger ejector and IMO a thicker neck will take the hit better. I have heard that .30 cal. 1,000 shooters can get better results with a clearance of .005 (I think that is the number.)
Re: Tight-neck brass thickness
The reamer I used had been reground to actually cut a 0.272" dia. neck chamber. My new Norma brass with a bullet inserted measures 0.272". Thus the need to shave the necks. I bought the reamer on this forum. I knew it was used but was not told it had been modified. Other-wise, everything else looks OK. Buyer beware!
The reamer I used had been reground to actually cut a 0.272" dia. neck chamber. My new Norma brass with a bullet inserted measures 0.272". Thus the need to shave the necks. I bought the reamer on this forum. I knew it was used but was not told it had been modified. Other-wise, everything else looks OK. Buyer beware!
Re: Tight-neck brass thickness
Well, the scope base arrived yesterday and I hit the range bright and early this AM. On break-in, the first 5 shots went inside an inch. The next two 5 shot groups averaged 0.516". I guessed at a load of 38.0 gr. of RL-17 and a 107 SMK jammed .015" into the lands. I used brass that was shaved to give me 0.004" neck clearance. The last two groups were somewhat round with no obvious fliers. This usually means I'm on the right track and groups will get better with tuning!
All-in-all, I'm happy with my first chambering job.
Dave
Well, the scope base arrived yesterday and I hit the range bright and early this AM. On break-in, the first 5 shots went inside an inch. The next two 5 shot groups averaged 0.516". I guessed at a load of 38.0 gr. of RL-17 and a 107 SMK jammed .015" into the lands. I used brass that was shaved to give me 0.004" neck clearance. The last two groups were somewhat round with no obvious fliers. This usually means I'm on the right track and groups will get better with tuning!
All-in-all, I'm happy with my first chambering job.
Dave
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