Just how bad is my shoulder bump consistency ?

[Wolfdog91]

So was about to load up some brass for my 5.56( BCA Bolt action AR with a 18" ballistic advantage 1/7 twist spr barrel

Prepped these last month and I usually don't go though every single one. Ill check head space on the first dozen or so and just roll with it . But today I decided why not and this is what I got

Think I used a RCBS small base die for this batch and ran out of one shot so had to use my old RCBS lube pad . Sizing on a RCBS rock chucker
Like I've said before I'm not chasing .0's but just a fairly consistent 1 MOA. But as far as things go for wanting that level of accuracy just how bad is this ?

Just curious, thanks

 

[WSnyder]

Like I've said before I'm not chasing .0's but just a fairly consistent 1 MOA. But as far as things go for wanting that level of accuracy just how bad is this ?

Approx -.002" to +.005" from median??? A nothing burger for accuracy sakes in that situation but something as far as potential case life. But it could and should be way better if you get your lube procedure sorted out.

 

[Bob in WI]

I think i see extreme spread of .002. Nothing I personally would worry about in a non bench gun. Brass springs back at different rates after sizing..nature of the beast.

 

[WSnyder]

I think i see extreme spread of .002.

1.459 - 1.452 = .007" It is larger than that because he shows 1.452 and under. How far under 1.452 was his shortest case?

Edit: I think I misread one of his 4's for a 9.

1.4556 - 1.452 = .0036 still a nothing burger

 

[Straightshooter1]

So was about to load up some brass for my 5.56( BCA Bolt action AR with a 18" ballistic advantage 1/7 twist spr barrel
View attachment 1647720
Prepped these last month and I usually don't go though every single one. Ill check head space on the first dozen or so and just roll with it . But today I decided why not and this is what I got
View attachment 1647721
Think I used a RCBS small base die for this batch and ran out of one shot so had to use my old RCBS lube pad . Sizing on a RCBS rock chucker
Like I've said before I'm not chasing .0's but just a fairly consistent 1 MOA. But as far as things go for wanting that level of accuracy just how bad is this ?

Just curious, thanks

Describe, in some detail, your flame annealing.

 

[Wolfdog91]

Describe, in some detail, your flame annealing.

In sort I do the flame change anneling method the guys from primal rights talk about. Do. Cheap cordless drill ,socket, propane torch. Try and hit it at the neck should junction and just spin it till I see the flame change. From my little experiments with it . Flame seems to cagne right around. The same time I get a bit of red glow on my brass right around the came mouth and into the neck a bit and when my 750° tempaqi does its thing

 

[Wolfdog91]

1.459 - 1.452 = .007" It is larger than that because he shows 1.452 and under. How far under 1.452 was his shortest case?

Edit: I think I misread one of his 4's for a 9.

1.4556 - 1.452 = .0036 still a nothing burger

Absolute shortest was 1.449

 

[WSnyder]

Absolute shortest was 1.449

1.4556 - 1.449 = .0066 Still accuracy wise on a 1MOA gun IMO = nothing.

 

[JFrank]

1.455 ( 6) ?
- 1.452
————
=0.003 I don’t see how a guy can get a 6 from a caliper that only displays 5/10000

 

[Straightshooter1]

In sort I do the flame change anneling method the guys from primal rights talk about. Do. Cheap cordless drill ,socket, propane torch. Try and hit it at the neck should junction and just spin it till I see the flame change. From my little experiments with it . Flame seems to cagne right around. The same time I get a bit of red glow on my brass right around the came mouth and into the neck a bit and when my 750° tempaqi does its thing
View attachment 1647740View attachment 1647741

You'll get more consistent results getting your necks hotter. I know. . . a lot of people worry about ruining the case, but it's really not that hard or that critical to the annealing done where you get more consistent shoulder bumps. You need a temperature of ~ 1,100 - 1,200°F for a second or two to get a more proper annealing. To get proper annealing with 750°F takes way too long (like, measured in minutes). When in a darkened room you see the neck turn red, that's a good indicator that your at ~1,200°F and you only need that for a second or two.

When I was annealing as you are doing, I too was getting similar variations in sizing as you. . . even when I incorporated a 5 second dwell time (leaving the case fully in the sizing die for a time to reduce springback). Since proper annealing process is a function of amount of heat over a period of time, a shorter amount of time with higher heat was needed. I've observed this in an AMP demonstration where I saw the case necks glow really red, but just for a moment. That got me to thinking, I really need to use more heat, though not for a much long time.

When I was using the "flame change method" it took 4-5 seconds to get that color change and I'd drop the case out of the flame. Now that I've gone to the "glow method", it takes ~ 9-10 seconds for a good glow and drop the case out of the flame at that point (.308 cases and 6.5 PRC cases). I make sure the flame is focused on the neck close to the shoulder and not much at the shoulder-body junction so that it's only the neck that glows. I find I get real consistent sizing and no issues for the case body.

Since I bought a hardness tester, I found it interesting how, in order to get the my target hardness the same as virgin Lapua brass, I had to get the necks just a little softer from the annealing as the sizing process brought the hardness up to my target hardness. I was a little surprised by how much the sizing process work hardens the brass.

So. . . you might experiment for yourself to see if you can improve your consistency??? Just don't point your flame at the shoulder, like in that second picture of yours.

 

[Evlshnngns]

I agree with not stressing this run. The variation in lube is enough for me to try the test again on a fresh batch.

Mark the extremes and measure them after firing.

 

[Coyotefurharvester]

If they all are LC23 brass you should be able to hold +,- 0.0015 from target HS. Which would be inside the +,- of your calipers( if consist with the press technique ).As mentioned get the flame up a touch on the necks, 7-8 count on the in flame time, if you're usually 5-6 seconds. BUT probably won't see anything different on target, and if you're running 2nd hand brass- no case life concerns(just get more).

 

[Steve Donlon]

I could never do a good job sizing brass with ONE SHOT and now always use a lube pad for more consistency. Also make sure to leave the ram up for a few seconds to let the brass set. I maybe going over board but I check every piece of sized brass for set back and if they need to go back a little more, set them a side to fix after I'm done. That way you can set your die to the minimum. Also for me it is much easier to check your brass with a RCBS Precision Mic Gauge. But that's just me. If it works for you that's great. You should have no trouble shooting sub MOA with your rifle. I should tell you how I fix the shoulders that are not pushed back enough. Most of the time just sizing them again will fix them, if not the trusty Redding Body die will push the shoulder back with out touching the neck.

 

[ToddKS]

If you really want to measure this consistently, I recommend getting the Short Action Precision kit. It is more consistent than the Hornady setup as you are not measuring a single linear point on the shoulder.

 

[KMW 1954]

Like I've said before I'm not chasing .0's but just a fairly consistent 1 MOA. But as far as things go for wanting that level of accuracy just how bad is this ?

Just curious, thanks

To the gist of the question. For what you are looking to do I would reply, Not enough to worry about.

I have sized a lot of different lots of brass using just everyday Lee dies. Some have come out on the money while others have turned out just as you describe. Even after annealing.

I load for target competition and normally look to push back .001". I measure every case as it come out of the sizing die. Many do not get the shoulders moved at all. The one that stumps me is, again, I measure every case and every now and then I get one that after being fired is shorter than when I loaded it..

 

[K22]

My thoughts based on my experience.

Measurement Issues:

When measuring in the .001ths, it does take much to induce inconsistent measurements.

I have seen those Hornady bump gauge and anvils induce inconsistency especially if you are dismantling them and remounting them on a caliper. Observed one anvil that was not parallel to the caliper jaws. Also, if the insert and holder are not aligned the same each time, inconsistency can result. Using match marks can help.

For this reason, I use a single piece bump gauge (Whidden) permanently mounted on a dedicated caliper. I greatly increased my measurement consistency.

Operator consistency can affect measurement consistency. Developing a consistent technique using uniform pressure on the caliper and rotating the case to "seat" it helps.

Cases:

Starting with virgin cases, dedicated to a specific rifle and rotating their use produces the best consistency in my experience.

Lube:

The best lube I've ever used in Imperial Sizing Wax. I was taught by a bench rest guy how to apply it to produce uniform lubing by using the thumb and two fingers. A 2 oz. tin will last over 5,000 lubing's. I never got a stuck case with Imperial and my sizing measurements got more consistent after I switch from One Shot to Imperial several years ago.

Bumping:

I set my sizing die for zero bump on the longest case (base to datum line). This way the shorter cases don't get oversized and tend to "catch up". This of course assumes that the longest case chambers optimally. Most guys are over sizing their cases for bolt rifles. Often when using a F/L die, a zero to .001 bump is all that is needed because the F/L die sizes the radial dimension of the case which is often the culprit in stiff chambering.

Annealing:

I do not anneal and know nothing about it other than if you are not doing properly, it can cause more harm than good. This is why I think those annealing machines would be the way to go if you want to anneal. It seems to take the guess work out of the process. Experienced annealers please chime in.

 

[Bob in WI]

1.459 - 1.452 = .007" It is larger than that because he shows 1.452 and under. How far under 1.452 was his shortest case?

Edit: I think I misread one of his 4's for a 9.

1.4556 - 1.452 = .0036 still a nothing burger

Somedays I swear I cant add 2+2! Appreciate the catch!

 

[Straightshooter1]

My thoughts based on my experience.

Measurement Issues:

When measuring in the .001ths, it does take much to induce inconsistent measurements.

I have seen those Hornady bump gauge and anvils induce inconsistency especially if you are dismantling them and remounting them on a caliper. Observed one anvil that was not parallel to the caliper jaws. Also, if the insert and holder are not aligned the same each time, inconsistency can result. Using match marks can help.

For this reason, I use a single piece bump gauge (Whidden) permanently mounted on a dedicated caliper. I greatly increased my measurement consistency.

Operator consistency can affect measurement consistency. Developing a consistent technique using uniform pressure on the caliper and rotating the case to "seat" it helps.

Cases:

Starting with virgin cases, dedicated to a specific rifle and rotating their use produces the best consistency in my experience.

Dedicated brass, especially fire formed to a specific rifle is, IMHO, very important.

Lube:

The best lube I've ever used in Imperial Sizing Wax. I was taught by a bench rest guy how to apply it to produce uniform lubing by using the thumb and two fingers. A 2 oz. tin will last over 5,000 lubing's. I never got a stuck case with Imperial and my sizing measurements got more consistent after I switch from One Shot to Imperial several years ago.

Yeah, that Imperial Sizing Die Was is GREAT! I've got over 13,000 lubing's (.308 and 6.5 PRC cases done and just finished with the tin. It just doesn't take much on the fingers to get the cases well lubed. Since I like to give ample dwell time when sizing, it's that time I take to lube a case. So, it's not like hand lubing each case adds any additional time to my case prep time.

Bumping:

I set my sizing die for zero bump on the longest case (base to datum line). This way the shorter cases don't get oversized and tend to "catch up". This of course assumes that the longest case chambers optimally. Most guys are over sizing their cases for bolt rifles. Often when using a F/L die, a zero to .001 bump is all that is needed because the F/L die sizes the radial dimension of the case which is often the culprit in stiff chambering.

I kinda agree about the .001 bump as it seems to work pretty well for me on my bolt guns where my bumps measure from .001 to .0015 (mostly at .0015).

Annealing:

I do not anneal and know nothing about it other than if you are not doing properly, it can cause more harm than good. This is why I think those annealing machines would be the way to go if you want to anneal. It seems to take the guess work out of the process. Experienced annealers please chime in.

Based on my experience with working on various alloy metals and doing a lot of brass case annealing, it's pretty hard to really "harm" things. As I see it, it's simply most of those that do the annealing simply don't know quite what they're doing to the metal and just follow what someone claims to work. Whatever one is doing with their annealing, I'd say what's most important is consistency and that's where the various annealing machines will help over doing it by hand and essentially guessing the amount of them. Though, depending on the precision one is after, annealing by hand may not be an issue in terms of precision and will do just fine in term of extending case life.

 

[DLT]

Turn the lights down when annealing. Trying to see what you need to see with them on is HARD

 

[Webster]

In sort I do the flame change anneling method the guys from primal rights talk about. Do. Cheap cordless drill ,socket, propane torch. Try and hit it at the neck should junction and just spin it till I see the flame change. From my little experiments with it . Flame seems to cagne right around. The same time I get a bit of red glow on my brass right around the came mouth and into the neck a bit and when my 750° tempaqi does its thing
View attachment 1647740View attachment 1647741

After viewing the Primal Rights Video my comments are:

All of his comments are personal opinion and not backed by real facts. He is just repeating the bad info that has been around for a long time. Looks like he gets uneven heating from the way the torches are aligned. I use one torch and center the flame on the neck. I push the inner cooler blue flame well into the neck so it wraps around the neck. I center the flame on the middle of the neck. I heat til I see the beginning of orange/red or whatever you call the color. Red for about 1 sec. It takes about 9 seconds with my method to get red. I don’t have the hottest part off the flame on the neck. The inner flame is cooler but larger and more uniform in temp. You cannot anneal at 750F. You need to get up around 1050-1100F to flash anneal. It’s normal for neck edge first abt 10 thou to get orange before the bulk of the neck. I have done annealing studies at work and performed hardness testing. Also collected and posted actual very detailed annealing studies published by the University of Illinois Metallurgy Dept.

Comments I disagree with in the video:

• Flame color change means cooking material out. Remove before color change.
• If you see the flame change color it’s a little too hot.
• Remove from flame before flame color change and you get proper anneal.
• Red color is too hot. The cases are ruined.