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russell m
Guest
With a 269 reamer,what thickness do you turn your necks to using a .243.3 bullet. russell m
jackie schmidt
New member
Russel
I wish I could tell you the actual thickness, but as you might know, I seat a bullet and actually measure the neck at the largest point and turn the necks accordingly
My loaded rounds will measure .2675, or there abouts. If I do make an error, I make sure it is to the loose side. I have shot with as much as .002 overall neck clearance, and can't really tell the difference.
I talked to a lot of shooters at The Nationals, and the trend seems to be toward more clearance, not less. .......jackie
I wish I could tell you the actual thickness, but as you might know, I seat a bullet and actually measure the neck at the largest point and turn the necks accordingly
My loaded rounds will measure .2675, or there abouts. If I do make an error, I make sure it is to the loose side. I have shot with as much as .002 overall neck clearance, and can't really tell the difference.
I talked to a lot of shooters at The Nationals, and the trend seems to be toward more clearance, not less. .......jackie
B
Big Al
Guest
You might recall that there are still a number shooters that use fitted neck in the PPC and give .0005 on a side. I myself have some barrels that still work out well using fitted necks.
RL Weikart
Member
Neck Clearance
If you look at Jackies measured thickness, .2675, after turning, he has elected to arrive with a total clearance of .0015. Take the .2675 and subtract .2433. The result is .0245, divide by 2 and you have .01225, this is your suggested neck thickness for a clearance of .0015. If this doesn't confuse you, I haven't done very good job.
If you look at Jackies measured thickness, .2675, after turning, he has elected to arrive with a total clearance of .0015. Take the .2675 and subtract .2433. The result is .0245, divide by 2 and you have .01225, this is your suggested neck thickness for a clearance of .0015. If this doesn't confuse you, I haven't done very good job.
Bob Kingsbury
New member
After subtracting .2433 from .2675, you have .0242. dividing that by 2
leaves a wall of .0121, not .0125. Now what is confusing about that ?
leaves a wall of .0121, not .0125. Now what is confusing about that ?
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russell m
Guest
Thank you very much for the help. russell m
I shoot a .270 neck chamber
and my loaded rounds measure .268. I have had much better results shooting with .002 than with tighter clearance. I played around with .001 and once in awhile I would get unexplained fliers. They went away with .002. I have even shot with .003 and it shot well, but there is no need to work the brass that hard.
Richard
and my loaded rounds measure .268. I have had much better results shooting with .002 than with tighter clearance. I played around with .001 and once in awhile I would get unexplained fliers. They went away with .002. I have even shot with .003 and it shot well, but there is no need to work the brass that hard.
Richard
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russell m
Guest
Would it be correct in saying that .0121 neck wall thickness would give me 0250 neck tension. Take a .0265 bushing minus the bullet .2433 minus the neck wall thickness .0121 = .0250 tension. Is this to much neck tension?
russell m
russell m
Gene Beggs
Active member
Russell,
Jackie and Bob are right on about .269 necks.
I use .269 necks with the 6mm Beggs cartridge and .250 necks with the 220 Beggs. With both cartridges neck wall thickness is .0120. I have carbide bushings available for both calibers. the 6mm uses .2660 and .2655 bushings and the 220 uses .2480 and .2475.
Bullet diameters vary slightly and in some cases, it is necessary to increase neck thickness to .0122 or so in order to get the desired neck tension. Thicker necks seem to be the norm in recent times and I have found they shoot best with .0020 clearance; never tighter than .0015. When I first started in benchrest back in '88, most shooters used either a .2610 or .2620 neck which required neck wall thicknesses of .0080 to .0085.
The thinner neck walls required .0020 squeeze to get the right neck tension but I have found the thicker necks used now require only .0010 squeeze. One would think it would be the other way around but that is not the case. How do I know this? I learned the hard way from investing several thousand dollars in the wrong size carbide bushings which had to be reground.
Don Neilson's 'Pumpkin' neck turner is the only one I am aware of that you can dial in to the tenth, the neck thickness desired.
Let me know if I can help you with anything.
Gene Beggs
Jackie and Bob are right on about .269 necks.
I use .269 necks with the 6mm Beggs cartridge and .250 necks with the 220 Beggs. With both cartridges neck wall thickness is .0120. I have carbide bushings available for both calibers. the 6mm uses .2660 and .2655 bushings and the 220 uses .2480 and .2475.
Bullet diameters vary slightly and in some cases, it is necessary to increase neck thickness to .0122 or so in order to get the desired neck tension. Thicker necks seem to be the norm in recent times and I have found they shoot best with .0020 clearance; never tighter than .0015. When I first started in benchrest back in '88, most shooters used either a .2610 or .2620 neck which required neck wall thicknesses of .0080 to .0085.
The thinner neck walls required .0020 squeeze to get the right neck tension but I have found the thicker necks used now require only .0010 squeeze. One would think it would be the other way around but that is not the case. How do I know this? I learned the hard way from investing several thousand dollars in the wrong size carbide bushings which had to be reground.
Don Neilson's 'Pumpkin' neck turner is the only one I am aware of that you can dial in to the tenth, the neck thickness desired.
Let me know if I can help you with anything.
Gene Beggs
Boyd Allen
Active member
Russell,
You have a the numbers right, but the zeros and decimal places need adjusting.
If you take the bullet at .2433 at the pressure ring (at the base) plus two times the neck wall thickness .0121 + .0121, you get a loaded round maximum neck diameter, over the bullet, of .2672, and if you subtract .265 from that you get .0022, which should be close to what your neck tension is. I say close to because I count neck tension as the actual difference between sized neck OD and loaded round OD, over the pressure ring, and brass has spring back, and bushings are not always as marked.
There is one more complication to your thicker necks, not a bad thing, but needing consideration. Thicker necks will give more bullet pull for a given amount of "neck tension", and it is the bullet pull that we are really concerned with. When you read discussions about neck tension for a tight necked 6 PPC, most of the time the writer is using something on the order of a .262 neck chamber, and as a result, his necks are thinner than yours. He will have less bullet pull for a given amount of sized case vs. loaded round diameter difference.
As to what neck clearance you should shoot for, as a result of a conversation with a much better shooter than I, I am about to turn a set of brass so that my loaded round clearance is around .0027. Normally, I am at less than .002. Of course you should also know that I know at least one good shooter that uses .0005 total clearance. Yes, it is confusing.
Boyd
You have a the numbers right, but the zeros and decimal places need adjusting.
If you take the bullet at .2433 at the pressure ring (at the base) plus two times the neck wall thickness .0121 + .0121, you get a loaded round maximum neck diameter, over the bullet, of .2672, and if you subtract .265 from that you get .0022, which should be close to what your neck tension is. I say close to because I count neck tension as the actual difference between sized neck OD and loaded round OD, over the pressure ring, and brass has spring back, and bushings are not always as marked.
There is one more complication to your thicker necks, not a bad thing, but needing consideration. Thicker necks will give more bullet pull for a given amount of "neck tension", and it is the bullet pull that we are really concerned with. When you read discussions about neck tension for a tight necked 6 PPC, most of the time the writer is using something on the order of a .262 neck chamber, and as a result, his necks are thinner than yours. He will have less bullet pull for a given amount of sized case vs. loaded round diameter difference.
As to what neck clearance you should shoot for, as a result of a conversation with a much better shooter than I, I am about to turn a set of brass so that my loaded round clearance is around .0027. Normally, I am at less than .002. Of course you should also know that I know at least one good shooter that uses .0005 total clearance. Yes, it is confusing.
Boyd
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russell m
Guest
More questions gene
When i cut my necks to 0118 this would give me a 0019 squeeze using a 265 bushing. Am I correct on this? Then if I used a 266 bushing I would get a 0009 squeeze. I may need to get a 265.5 bushing.
russell m
When i cut my necks to 0118 this would give me a 0019 squeeze using a 265 bushing. Am I correct on this? Then if I used a 266 bushing I would get a 0009 squeeze. I may need to get a 265.5 bushing.
russell m
Gene Beggs
Active member
Russ, you will just have to try it and see. Between the .2660 and .2655 bushings, you should be able to accommodate most any 6mm bullet by varying the neck thickness a couple of tenths one way or the other. Boat tails usually require a little more squeeze than do flat base bullets. Best of luck to you in 2010.
Gene Beggs
goodgrouper
tryingtobeabettergrouper
interesting.....
This really has nothing to do with what anyone has said here but I just read Tony Boyer's interview in PS from this summer and I thought it was interesting that Tony has gone to a .269 neck reamer. I guess those of us that have tinkered with .269's in 6mm aren't so crazy after all!
This really has nothing to do with what anyone has said here but I just read Tony Boyer's interview in PS from this summer and I thought it was interesting that Tony has gone to a .269 neck reamer. I guess those of us that have tinkered with .269's in 6mm aren't so crazy after all!
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Bob Kingsbury
New member
Boyd
You may need to replace the batteries in your calculator.
.2433 + .0121+ .0121 = .2675
You may need to replace the batteries in your calculator.
.2433 + .0121+ .0121 = .2675
CYanchycki
Club Coordinator
I hope
that is what will be my issue.
With the winter blues setting in I decided to check clearance of my loaded rounds. I did not think they were that tight but they were. My loaded rounds were measuring around .2682 for a .269 neck. I returned the necks on those 25 just skimming a tad off and then returning the necks of my new brass. Loaded rounds of the new are .2672. Feel a bit better now. Hopefully it may show on paper.
Calvin
that is what will be my issue.
With the winter blues setting in I decided to check clearance of my loaded rounds. I did not think they were that tight but they were. My loaded rounds were measuring around .2682 for a .269 neck. I returned the necks on those 25 just skimming a tad off and then returning the necks of my new brass. Loaded rounds of the new are .2672. Feel a bit better now. Hopefully it may show on paper.
Calvin
JerrySharrett
Senile Member
russell, don't worry about neck wall thickness...too hard to get a consistent measurement. Seat a bullet and measure the diameter of that. Simple!!