A good example of the effect of neck tension

[Alex Wheeler]

I met a buddy at the range to see how his 25 prc I chambered was tuning up. This is such a great example of how much neck tension can effect the tune. I really struggle getting this across to some people so pictures like this are great. 2 ladders shot back to back at 600 in mild conditions. The only difference is one is .002nt and the other .005nt. Just look at the holes with the letters next to them. Those letters correspond to the colors he marked the bullets. Theres extra holes from other days on the target. Had he only shot the ladder with .002nt we probably would have imediately switched powders. But with .005nt it kept 1.5gn.s of powder under 3 inches of vertical at 600.

 

[Alex Wheeler]

This is what I mean when I say a rifle is untunable if your on the wrong bushing

 

[Willys]

Is the lower hole in top pic not part of group?

 

[Alex Wheeler]

No thats a 6mm hole. Theres 6 shots in each ladder

 

[Broz]

I guess I am a little confused on this?

"The only difference is one is .002nt and the other .005nt. Just look at the holes with the color numbers."

 

[Alex Wheeler]

 

[Alex Wheeler]

I guess I am a little confused on this?

"The only difference is one is .002nt and the other .005nt. Just look at the holes with the color numbers."

I edited it, letters. Not numbers, lol

 

[Masterdunbar]

Alex
I’m sure you’ve mentioned this in the past, but was curious if you could reiterate where in the tuning process you place neck tension testing. Typical process for me is
Pressure test
Ladder test
Seating depth
Back to a fine ladder test

 

[Homebrewer]

which column is the .005" nt ?

284 --> 282 or 286 --> 285 ??

 

[Alex Wheeler]

which column is the .005" nt ?

284 --> 282 or 286 --> 285 ??

The one on the left. To explain those numbers, the 284 bushing produced a 282 neck od. The 286 produced a 285 od. Never trust the numbers on a bushing

 

[Alex Wheeler]

Alex
I’m sure you’ve mentioned this in the past, but was curious if you could reiterate where in the tuning process you place neck tension testing. Typical process for me is
Pressure test
Ladder test
Seating depth
Back to a fine ladder test

Normally its down the list. I will run a pressure ladder first. Im looking for a charge area to start shooting 3 shot groups around and where it will pressure out. Second I shoot 3 shot groups to tune powder. Then seating depth. Back to powder, the neck tension. Since you should not tune on green barrels or new brass, I sometimes will use that time to run multiple pressure ladders with different primers. Just to pick out a primer. But sometimes like in this example Im not so sure we shouldnt do it first.

 

[Gord0]

I hadn't ever played with neck tension before, but around 2yrs ago I decided to pick some up for my win mag. I used a load that was proven accurate with my old sizing die. It was only at 100m, but it was great to see the changes with my own eyes. I dialed my scope down for that last group, which I wish I hadn't

 

[doc88]

Normally its down the list. I will run a pressure ladder first. Im looking for a charge area to start shooting 3 shot groups around and where it will pressure out. Second I shoot 3 shot groups to tune powder. Then seating depth. Back to powder, the neck tension. Since you should not tune on green barrels or new brass, I sometimes will use that time to run multiple pressure ladders with different primers. Just to pick out a primer. But sometimes like in this example Im not so sure we shouldnt do it first.

Do you think there is a correlation between bullet seating depth and neck tension preference. In other words, a bullet seated deep in the neck needing lighter neck tension vs a bullet seated say only halfway down the neck needing more neck tension. I understand testing is only sure way to know but just wondering about a trend here.

 

[Willys]

I would think a fresh annealed case would be less sensitive to bushing changes vs a work hardened neck ? And maybe a work hardened neck needs .0005 to .002 larger neck vs annealed case to get same tension ????

 

[Alex Wheeler]

Do you think there is a correlation between bullet seating depth and neck tension preference. In other words, a bullet seated deep in the neck needing lighter neck tension vs a bullet seated say only halfway down the neck needing more neck tension. I understand testing is only sure way to know but just wondering about a trend here.

No. I have played with hard jams to big jumps and I have not seen any change in the neck tension preference. Even in our bench guns that we seat into the lands, they still like .005nt"

 

[Alex Wheeler]

I would think a fresh annealed case would be less sensitive to bushing changes vs a work hardened neck ? And maybe a work hardened neck needs .0005 to .002 larger neck vs annealed case to get same tension ????

I dont think you can achieve the same tension with annealed brass as you can with non annealed brass. In the cartridges that didnt like annealed brass, we could not find a way to make them shoot no matter what we did with bushings.
A few guys in 1kbr did find that the guns shot best on the second firing after annealing. So they shot the annealed brass in the sighter period. Did not anneal it, loaded it for the record period and shot it. Then they repeated the cycle.

 

[parshal]

In the cartridges that didnt like annealed brass, we could not find a way to make them shoot no matter what we did with bushings.

My teammate and I have a 6.5 Creed load that was fantastic with brand new brass. The groups are a little larger with the once-fired and I had read this thread and thought about different bushings. I'd also thought about lowering the AMP setting in 2-3 setting increments and see if there was a spot where it tightened up. Did you test that before I waste my time?

Note, this load is for NRL Hunter and is still plenty accurate as is but we've been wondering if this thread applied so I was going to test it.

 

[matt_3479]

Out of curiosity as I know it changes so much dependant on too many variables but you did mention in an above post that “even your bench guns still like .005 nk tension”, so my question is are you noticing that more often then not that more neck tension is providing better accuracy? It’s always told that .001-.002 thou neck tension is best, but you’ve mentioned multiple times that you run a lot at .004,.005, .006 thou neck tension.

I have a new br arriving Wednesday or Thursday and I’m now going to be testing this neck tension more in my br and my new bra barrel once my currents don’t (any round now lol).

 

[Masterdunbar]

Out of curiosity as I know it changes so much dependant on too many variables but you did mention in an above post that “even your bench guns still like .005 nk tension”, so my question is are you noticing that more often then not that more neck tension is providing better accuracy? It’s always told that .001-.002 thou neck tension is best, but you’ve mentioned multiple times that you run a lot at .004,.005, .006 thou neck tension.

I have a new br arriving Wednesday or Thursday and I’m now going to be testing this neck tension more in my br and my new bra barrel once my currents don’t (any round now lol).

A lot of us are seeing higher tension to be better. Out of the 4 latest guns I’ve worked on all have preferred .004 over 0.003 or 0.002.

 

[matt_3479]

A lot of us are seeing higher tension to be better. Out of the 4 latest guns I’ve worked on all have preferred .004 or 0.003 or 0.002.

Thank you! I’ll definitely spend more time in this department. Im definitely interested in seeing the best order to go about load development.

 

[windypants]

With my 30-28, I'm experimenting with not annealing. With 1X fired brass and .332 bushing, I got a pretty consistent .303 neck ID that shot great. With 2X fired brass, the .332 bushing gives me a less consistent .304-.305 ID and it shoots good, but not quite as well. I tried a .331 bushing (.299 ID) followed with a .3025 mandrel and the group was slightly worse. So definitely up in the air as to how this is going to play out.

I have noticed that redding bushings size smaller than the wilson bushings. My 332 and up bushings are wilson and the 331 is redding and sizes smaller in proportion to its size, so I want to try the wilson .331 to see if it will give the desired .303 ID. I've seen this discrepency with my .25 cal bushings also.

Always lots to learn--keeps it interesting!

 

[Masterdunbar]

Thank you! I’ll definitely spend more time in this department. Im definitely interested in seeing the best order to go about load development.

Matt I noticed a typo in my message to you.
"Out of the 4 latest guns I’ve worked on all have preferred .004 OVER the lighter tensions of 0.003 or 0.002."

 

[Masterdunbar]

With my 30-28, I'm experimenting with not annealing. With 1X fired brass and .332 bushing, I got a pretty consistent .333 neck ID that shot great. With 2X fired brass, the .332 bushing gives me a less consistent .334-.335 ID and it shoots good, but not quite as well. I tried a .331 bushing (.329 ID) followed with a .3025 mandrel and the group was slightly worse. So definitely up in the air as to how this is going to play out.

I have noticed that redding bushings size smaller than the wilson bushings. My 332 and up bushings are wilson and the 331 is redding and sizes smaller in proportion to its size, so I want to try the wilson .331 to see if it will give the desired .333 ID. I've seen this discrepency with my .25 cal bushings also.

Always lots to learn--keeps it interesting!

It is scenarios like that which make me wonder how modern day snipers figure out their guns and load. Are the military grade weapons so consistent that they all shoot the same damn thing and are sub 1/2 each ? Or does each person have to get into the weeds on things like we do? how can a sniper go from the mountains of Pakistan down to the seasides of the ocean and still know he is going to hit that 8" target 2k away???

 

[FURMAN]

I think the shooting skills of snipers are way over estimated. The equipment is for sure. Ryan Cleckner talks a little bit about this with Erik on a podcast.

 

[windypants]

It is scenarios like that which make me wonder how modern day snipers figure out their guns and load. Are the military grade weapons so consistent that they all shoot the same damn thing and are sub 1/2 each ? Or does each person have to get into the weeds on things like we do? how can a sniper go from the mountains of Pakistan down to the seasides of the ocean and still know he is going to hit that 8" target 2k away???

I've wondered about that also!

 

[Masterdunbar]

I think the shooting skills of snipers are way over estimated. The equipment is for sure. Ryan Cleckner talks a little bit about this with Erik on a podcast.

 

[FURMAN]

View attachment 14478

The majority of their skill set is in other areas that I know I can't compete with.

 

[Alex Wheeler]

My teammate and I have a 6.5 Creed load that was fantastic with brand new brass. The groups are a little larger with the once-fired and I had read this thread and thought about different bushings. I'd also thought about lowering the AMP setting in 2-3 setting increments and see if there was a spot where it tightened up. Did you test that before I waste my time?

Note, this load is for NRL Hunter and is still plenty accurate as is but we've been wondering if this thread applied so I was going to test it.

Most of the time new brass wont shoot anything like fired brass. It can be very different. Different nt, powder charge, and seating depth. I wont do any tuning on new brass anymore. So, you will need to start from scratch. Just work up a load like it was a new gun. Focus on neck tention first. I dont own an amp so no I didnt do what you say. But when i had my bench source i did play with the amount i annealed. Id play with bushings first.

 

[Alex Wheeler]

Out of curiosity as I know it changes so much dependant on too many variables but you did mention in an above post that “even your bench guns still like .005 nk tension”, so my question is are you noticing that more often then not that more neck tension is providing better accuracy? It’s always told that .001-.002 thou neck tension is best, but you’ve mentioned multiple times that you run a lot at .004,.005, .006 thou neck tension.

I have a new br arriving Wednesday or Thursday and I’m now going to be testing this neck tension more in my br and my new bra barrel once my currents don’t (any round now lol).

Most of the time, but not always.

 

[matt_3479]

Most of the time, but not always.

Thanks Alex

 

[stlhdr1]

Most of the time new brass wont shoot anything like fired brass. It can be very different. Different nt, powder charge, and seating depth. I wont do any tuning on new brass anymore. So, you will need to start from scratch. Just work up a load like it was a new gun. Focus on neck tention first. I dont own an amp so no I didnt do what you say. But when i had my bench source i did play with the amount i annealed. Id play with bushings first.

Alex,

You mentioned not owning an AMP. Does this statement mean you don't use one? Curious what your process is in keeping the brass softer/workable?

Keith

 

[Okie man]

With my 30-28, I'm experimenting with not annealing. With 1X fired brass and .332 bushing, I got a pretty consistent .333 neck ID that shot great. With 2X fired brass, the .332 bushing gives me a less consistent .334-.335 ID and it shoots good, but not quite as well. I tried a .331 bushing (.329 ID) followed with a .3025 mandrel and the group was slightly worse. So definitely up in the air as to how this is going to play out.

I have noticed that redding bushings size smaller than the wilson bushings. My 332 and up bushings are wilson and the 331 is redding and sizes smaller in proportion to its size, so I want to try the wilson .331 to see if it will give the desired .333 ID. I've seen this discrepency with my .25 cal bushings also.

Always lots to learn--keeps it interesting!

Wilson bushings are tapered, the end with size stamped is .003 smaller than the other end. The actual size that is stamped on bushing is in the middle of bushing.

 

[Gord0]

Wilson bushings are tapered, the end with size stamped is .003 smaller than the other end. The actual size that is stamped on bushing is in the middle of bushing.

They are definitely not .003" smaller on the stamped end. Maybe .0003". I could take one into work and measure it precisely, but it would only be a sample of 1

 

[windypants]

Wilson bushings are tapered, the end with size stamped is .003 smaller than the other end. The actual size that is stamped on bushing is in the middle of bushing.

I thought maybe they were tapered, but couldn't tell for sure if my caliper was giving me a good enough reading. I've been using them stamped side up. Maybe if I flip it over, I can get closer to that .303 ID I want. I'll check that out tomorrow.

 

[Okie man]

The instructions that came with die say you can if you’re fighting spring back. I just bought 4 different sizes when I got the die.

 

[MECA]

i RECENTLY SWITCHED FROM REDDING TO SAC BUSHINGS FOR BOTH MY 22-6MM AI AND MY 6.5X284!
I LIKE THEM MUCH BETTER!
JUST SAYING!

 

[windypants]

The instructions that came with die say you can if you’re fighting spring back. I just bought 4 different sizes when I got the die.

Thanks for the tip! I flipped the bushing and got the .303 +/-.0005 ID I'm wanting. I was using these bushings in a redding and now a micron die, so I didn't have the wilson die instructions. Also tried it on 3X fired brass and it worked with that too, so not annealing appears to be working so far. But I'll still have to confirm on a LR target.

 

[Okie man]

i RECENTLY SWITCHED FROM REDDING TO SAC BUSHINGS FOR BOTH MY 22-6MM AI AND MY 6.5X284!
I LIKE THEM MUCH BETTER!
JUST SAYING.

I’ve seen the SAC bushings mentioned several times now. All say they are really nice.

 

[bigbulls]

After reading through this thread I had to go to the reloading room and do some measuring. I have 15 different Redding titanium bushing and using my pin gauge set they all are .001 smaller then the number stamped on the top, both ends the same. I'm guessing that's because of spring back. I will be checking that the next time I'm resizing with my blade micrometer.

 

[FURMAN]

Yes, if you measure with a gage after bushing sizing it never matches. I use pin gages to determine the "tension" I am actually getting.

 

[CanadianPlinker]

It sounds like most here are using bushings for neck tension. Is there a reason why you use them over an expander mandrel?

 

[Willys]

Mandral is just for the last .0005

 

[matt_3479]

i RECENTLY SWITCHED FROM REDDING TO SAC BUSHINGS FOR BOTH MY 22-6MM AI AND MY 6.5X284!
I LIKE THEM MUCH BETTER!
JUST SAYING!

I recently picked up a couple SAC dies and lord are they nice! I necked a bunch of brass down with them for one caliber and pick up another for my new rifle and started loading last night with them. I really really like them!

 

[ccass]

Great discussion here particularly regarding what tension there actually is after neck sizing ( by mandrel or bushing).
I AMP anneal after every firing and use the bushing then mandrel method. My brass is either Lapua, ADG or Alpha depending on caliber. Recently I bought some quality pin guages in .0005 increments for my 6mm and 284 to start checking my loads for consistency. The results were interesting. On 2x fired Lapua, I found there was .001 spring back. On 10x fired Alpha 6mm brass, I found no spring back. I also found by setting my calipers to the pin guage size, that not all mandrels are the same size as advertised.
So questions on where to go from here. Ryan, it sounds like you already use pin guages to determine what your true tension is. Do you also see where brass is becoming work hardened after multiple firings because the spring back is gone? Alex, do you use pin guages as the final true measurement? Are we splitting hairs worrying about .001 tension in precision rifles?
Thx

 

[FURMAN]

It sounds like most here are using bushings for neck tension. Is there a reason why you use them over an expander mandrel?

I have experimented extensively with mandrels and buttons. Buttons induce too much runout. Mandrels and bushing differences can not be seen on target if the same tension is used according to a pin gage.

 

[Willys]

Advantage of pin guages versus measuring neck OD before and after seating a bullet?

 

[FURMAN]

Advantage of pin guages versus measuring neck OD before and after seating a bullet?

The pin gage tells you exactly how much "tension" you will have. The way you are suggesting is just not an accurate way to measure and neither is using calipers on the ID. Ultimately it does not matter as long as the method you are using is repeatable and you are testing. The issue only really becomes an issue if you are trying to relay information to someone else.

 

[matt_3479]

The pin gage tells you exactly how much "tension" you will have. The way you are suggesting is just not an accurate way to measure and neither is using calipers on the ID. Ultimately it does not matter as long as the method you are using is repeatable and you are testing. The issue only really becomes an issue if you are trying to relay information to someone else.

Is there a set of pin gauges you recommend?

 

[parshal]

I grabbed three full sets off Amazon but I also use them for machine work. I bought a few in .0005" increments, too. Honestly, you can get expensive ones that have better accuracy guarantees but, as long as you use the same set, it's consistency that matters as stated earlier.

 

[FURMAN]

They can be purchased on amazon but I own K&M.

Gage Pins - K+M Precision Shooting Products

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