How do you incorporate neck tension into your load development?

[Bill Norris]

Another question for y'all. I've been using Wilson bushings for sizing with no further work. Would sizing small and necking back up with a mandrel offer any advantages?

I have tried that with some of my rifles and although I can't say my groups are smaller due to it I don't think it hurts at all.

 

[Bottom Fodder]

I hear ya, but the dang bullets cost $.60 each and an itty bitty primer costs a dime. Never mind the $700 barrel that you can use the better(best) part of its life testing loads. On top of that it takes a year to get a barrel and good 'smiths ain't sitting around waiting for work. Whew! I feel better now that I got that out

I hear y’all , but do you not won’t the most accuracy out of they 60 cent bullet and 10 cent primer and $700 barrel plus powder out of your gun with you pulling the trigger. Glad I got you to vent so you feel better
just my $0.02 that’s worth about $0.01

 

[AlNyhus]

Starting with the bullet .030 past the T.P. and a neck bushing .004 smaller than the loaded round measures, my steps are (in order):
-Powder charge
-Seating depth with the best charge wt
-Loosen up neck tension .001 at a time

 

[6.5 forever]

My idea about neck tension is that it must be consistent. How much tension is secondary?....

 

[HTSmith]

Starting with the bullet .030 past the T.P. and a neck bushing .004 smaller than the loaded round measures, my steps are (in order):
-Powder charge
-Seating depth with the best charge wt
-Loosen up neck tension .001 at a time

That makes a lot of sense sir.

 

[seymour fish]

My idea about neck tension is that it must be consistent. How much tension is secondary?....

Agree. Lacking any proper tools, consider a well-calibrated Kinetic bullet puller

 

[spudgun]

Reading this post has me thinking.

I have noticed that when I seat my bullets some are as smooth as silk and other take a higher pressure to start the seating motion.

I have wondered many times shooting at 1K, why one shot would be .5-1 MOA higher that the group. I'm thinking maybe the higher tension was causing the pressure to build higher in the case before the bullet started moving. Thus causing a higher FPS at the target (some times as high as 40 FPS faster) to cause the higher POI.

The next time I seat my bullets I will take the ones that took a little more pressure to start it, mark them and see if my thinking is correct.

 

[Bill Norris]

Reading this post has me thinking.

I have noticed that when I seat my bullets some are as smooth as silk and other take a higher pressure to start the seating motion.

I have wondered many times shooting at 1K, why one shot would be .5-1 MOA higher that the group. I'm thinking maybe the higher tension was causing the pressure to build higher in the case before the bullet started moving. Thus causing a higher FPS at the target (some times as high as 40 FPS faster) to cause the higher POI.

The next time I seat my bullets I will take the ones that took a little more pressure to start it, mark them and see if my thinking is correct.

40 FPS is definitely gonna change your POI at longer ranges.

 

[spudgun]

40 FPS is definitely gonna change your POI at longer ranges.

Yep, I have been scratching my head for over a year on why 1 shot out of 5 would be high or low when the rest are in the 10 group. Every time it happens I look at the FPS on the target and notice that it is different than the others.

I know my powder, primers, bullets, seating depths and cases are the same.

Going out on Wed and check it out.

 

[AlNyhus]

I know my powder, primers, bullets, seating depths and cases are the same.

Are you stress relieving the necks? What style of neck chamfering tool?

 

[ShtrRdy]

Starting with the bullet .030 past the T.P. and a neck bushing .004 smaller than the loaded round measures, my steps are (in order):
-Powder charge
-Seating depth with the best charge wt
-Loosen up neck tension .001 at a time

I have to ask a dumb question, ...... what does T.P. mean in this context?

 

[RegionRat]

T.P. = touch point

ETA: he was referring to the seating depth where the ogive touches the lands.

 

[dmoran]

Below is a 1000yd Neck-tension test that shows significant variation in dispersion between 0.001" increments in bushings used:

 

[jimmymac]

Are you stress relieving the necks?

Mandrel after sizing? Not sure what you are referring to. Can you help a brother out?

 

[HTSmith]

Below is a 1000yd Neck-tension test that shows significant variation in dispersion between 0.001" increments in bushings used:


View attachment 1443656

Good Stuff right there! Did you settle on 263?

 

[Pres100]

Below is a 1000yd Neck-tension test that shows significant variation in dispersion between 0.001" increments in bushings used:


View attachment 1443656

Nice results.
Can you expand on the:

• cartridge,
• brass used,
• neck thickness and
• chamber neck dimensions ?

 

[AlNyhus]

Mandrel after sizing? Not sure what you are referring to. Can you help a brother out?

Jim, it's the 'a-word'.....'annealing'.

 

[chop house]

both bill's and donovan's targets show more vertical when neck tension is decreased. if that is a trend, i think you guys have turned on a light bulb. i do anneal but seldom jam, often struggle with poor sealing necks, and also get vertical that i attribute to me. i am going exploring.

for those that measure seating force, what kind of numbers are you looking for?

 

[JMayo]

For me, Jamming = less neck tension needed.
My groups in both 30br & 6bra spread out with hvy seating pressure.
On my k&m the seating starts at 10 & finished at 30. Anything over that caused flyers.

 

[Fast14riot]

For me, Jamming = less neck tension needed.
My groups in both 30br & 6bra spread out with hvy seating pressure.
On my k&m the seating starts at 10 & finished at 30. Anything over that caused flyers.

I have noticed this with my 6br as well. I shoot the 107smk jammed and when I tested neck tension I found using a .266 bushing was best. 265 and 264 opened groups up.

I test neck tension concurrent to seating depth.