AMP annealing gone wrong?

[Awesymoto]

hey guys, Recently got an AMP annealing machine for my reloading, its slick. I had a pet load for my 300 PRC that shoots pretty good, and duplicated it, same brass prep, same charge, seating depth etc… Well I got an AZTEC code of 150, and went to the range to find out it shoots pretty bad. I use a .3070 expander mandrel, and the group on the left (.2MOA ish) is the old blow torch method of annealing.

Now i’m kind of confused has anybody seen the same issues? After I grouped the two on the right top and bottom (forgive the crap pictures I took it in the sun and couldn’t see the groups / framing on my iPhone) I was scratching my head so I shot the old load and it grouped fine. I chrono’d the loads and they both were the same average and same SD.

 

[tthomp302]

One thing to make sure of is if your shoulder bump changed due to the lack of/difference in spring back. If you didn't change your die set up, that may be something to look at.

 

[straightshooter1]

hey guys, Recently got an AMP annealing machine for my reloading, its slick. I had a pet load for my 300 PRC that shoots pretty good, and duplicated it, same brass prep, same charge, seating depth etc… Well I got an AZTEC code of 150, and went to the range to find out it shoots pretty bad. I use a .3070 expander mandrel, and the group on the left (.2MOA ish) is the old blow torch method of annealing.

Now i’m kind of confused has anybody seen the same issues? After I grouped the two on the right top and bottom (forgive the crap pictures I took it in the sun and couldn’t see the groups / framing on my iPhone) I was scratching my head so I shot the old load and it grouped fine. I chrono’d the loads and they both were the same average and same SD.

I was just going to say, did you check the case dimensions before charging to see if they were the same as the old for might be a difference in spring back . . . particularly the amount of bump?

 

[rustyinbend]

My 300-PRC AMP code with Lapua brass is 168 ... so your 150 is in the ballpark and should be just fine. Can't imagine that the annealer is causing this, but I suppose it's possible. Frankly, I'd look elsewhere for the answer.

 

[Awesymoto]

I re-adjusted the die for datum off my comparator from 2.1945-2.1950“ fired to 2.1940” resized, and backed off my seating die .003-.004 for the same seating depth.

 

[Awesymoto]

my only thought is the neck tension is less, now that it’s annealed and maybe that’s the issue? the barrel is right at 450 rounds,
the bore looks good to me still

 

[ZY100]

For some reason, induction annealing leaves a different type of residue/oxide in the neck. Had similar results.

I throw annealed and sized brass in the tumbler with used media for 4-5 hours and it fixed it.

You may need to fine tune neck tension/seating as well.

ZY

 

[RegionRat]

Whenever you have what you call a "good load" and you make a change and then you don't like the load.... isn't the thing to do to go back a step and see if something else was the problem?

Nothing wrong with asking out loud in a forum, but the inevitable advice is to go back and test your process without the annealing first, and then ask how to tune your load with that change.

Depending on if your load is "good" again, then we have a different question to begin with, and if your load is bad without the annealing, we again have a different question to begin with.

 

[918v]

How are you sizing the case? How much is your die taking the neck down before you expand it back out?

 

[Awesymoto]

How are you sizing the case? How much is your die taking the neck down before you expand it back out?

I’m using a .334 neck bushing loaded OD is .3370

 

[Awesymoto]

Whenever you have what you call a "good load" and you make a change and then you don't like the load.... isn't the thing to do to go back a step and see if something else was the problem?

Nothing wrong with asking out loud in a forum, but the inevitable advice is to go back and test your process without the annealing first, and then ask how to tune your load with that change.

Depending on if your load is "good" again, then we have a different question to begin with, and if your load is bad without the annealing, we again have a different question to begin with.

Good point the past 3 lots of 50 I‘ve loaded, though were the same and all around a half to 6th’s a MOA.

 

[RegionRat]

Good point the past 3 lots of 50 I‘ve loaded, though were the same and all around a half to 6th’s a MOA.

I would take some of the fired brass, skip the annealing, and see what you get with a quick test.

By itself, the neck tension can cause tuning issues. There is a cycle by cycle increase in the work hardening on necks and shoulders without annealing. If your tune was so sensitive to a slight change in neck tension or friction coefficient, then you will have to decide on the re-tune with annealing, or just skip it.

So try to keep in mind that how the combustion cycle starts when the case neck is holding the bullet is important because it sets the combustion trend but very soon after other factors take over.

That neck is both the force and the friction holding the bullet, so you may need to re-tune the load for both reasons, the neck tension as well as the friction changes. YMMV.

 

[918v]

I’m using a .334 neck bushing loaded OD is .3370

Is your seating effort harder/different after annealing? Are you using dry lube?

 

[CK1.0]

Using the AMP every firing will get you brass that's crazy consistent firing to firing, it's almost like a "reset button" for cases.

But you'll still need to come up with a specific load recipe using your freshly annealed "new" brass. Post-AMP the brass has changed from what you were using previously and is its own thing.

The payoff comes after you find a solid load with the AMP'd stuff, then, going forward, you won't have to change shit and the stuff will shoot near the same whether 3rd firing or 13th firing (and cases will make it that far if you don't beat on them too hard).

 

[Cascade Hemi]

There are a bunch of threads just like this one.

 

[918v]

There are a bunch of threads just like this one.

Because people assume things

 

[Awesymoto]

Is your seating effort harder/different after annealing? Are you using dry lube?

no dry lube just brushing the case necks, but the seating pressure is definitely lighter… feels like very low resistance.

 

[Awesymoto]

Using the AMP every firing will get you brass that's crazy consistent firing to firing, it's almost like a "reset button" for cases.

But you'll still need to come up with a specific load recipe using your freshly annealed "new" brass. Post-AMP the brass has changed from what you were using previously and is its own thing.

The payoff comes after you find a solid load with the AMP'd stuff, then, going forward, you won't have to change shit and the stuff will shoot near the same whether 3rd firing or 13th firing (and cases will make it that far if you don't beat on them too hard).

This is what I’m assuming, I may just suck it up and do another load dev.

 

[918v]

no dry lube just brushing the case necks, but the seating pressure is definitely lighter… feels like very low resistance.

There u go

 

[CK1.0]

This is what I’m assuming, I may just suck it up and do another load dev.

More than likely it's your neck tension that has changed... If it were me, I'd go to bushing a couple thou tighter than before and see what I got?

There's no real need to worry about overworking the brass anymore with the AMP in the mix every firing.

As an aside, I've actually been experimenting with purposely squashing my necks down more than I used to with smaller bushings before opening them back up with a mandrel... playing with the amount of engagement I want to get with the mandrel. I'm finding I can get some "free speed" without doing anything else if I want, and/or lower my SD/ES numbers by just playing with that... neat stuff.

 

[918v]

This is what I’m assuming, I may just suck it up and do another load dev.

You can add powder or use a tighter bushing, or reduce the annealing setting.

When you had the AMP analyze the case, did you input the correct bushing number? Maybe you’re over annealed the cases?

 

[Awesymoto]

You can add powder or use a tighter bushing, or reduce the annealing setting.

When you had the AMP analyze the case, did you input the correct bushing number? Maybe you’re over annealed the cases?

I used 031B for 300 PRC if I recall that’s what the webpage said

 

[918v]

I used 031B for 300 PRC if I recall that’s what the webpage said

Then your analysis should be good. I think the problem is bushing dies don’t size the whole neck and this reduces seating effort over standard dies. Less seating pressure, less velocity. Do you got to make that up somehow.

 

[Wizard1183]

This is what I’m assuming, I may just suck it up and do another load dev.

That’s what you have to do after annealing

 

[tarm]

Then your analysis should be good. I think the problem is bushing dies don’t size the whole neck and this reduces seating effort over standard dies. Less seating pressure, less velocity. Do you got to make that up somehow.

Unless he is seating the bt/bdy junc into or past the case's shld/nk jnc that small amount of unsized neck should have little to no effect. He is using a mandrel after bushing nk size this would negate any tension force change Regardless, he is using the same process sans the addition of the AMP annealing.

IMO, either anneal everytime or not at all for neck tension stability. Obviously the latter could decrease case life and require adj of the die. The other possibility is tuning the annealer code for a shorter time period. To me it seems the ideal annealing for his current load would be to stabilize the neck stress/hardness to what it was when he developed the load. You could simply try dropping the code number in 5 point steps and shoot the groups till you see it dial in. The other would be to work the case neck a bit more. Not sure how far you are sizing it down then expanding it. Going to far can possibly increase runout vs possibly running it thru the bushing and expander twice. Obviously there's a few ways to attack this.

The other thing is neck lube. Be it, leaving the carbon in or cleaning and then using graphite,Hbn, or moly to coat the inside neck surface. My preference is to the latter using Hbn prior to mandrel expanding, allowing the mandrel to burnish it in. It will also prevent cold welding if the ammo sits for months before use. I find the most consistent seating force traces using this specific method.

My advice is only change one thing at a time, testing and recording the results. I find neck tension mostly seems to effect vel spread but not the over all mean vel by much. Now if the load is on the edge of or in a very narrow node just about any small change can bust it open.........

 

[iceng]

Ill echo everyone else. Do load dev again. I had the same issue (sort of). Did a powder test again, and seating depth, and neck tension (bushing vs mandrel).

I had to make minor changes, and the groups became way more consistent.

You have the right tools for the job, so use them properly and extract the potential !

 

[Awesymoto]

Ill echo everyone else. Do load dev again. I had the same issue (sort of). Did a powder test again, and seating depth, and neck tension (bushing vs mandrel).

I had to make minor changes, and the groups became way more consistent.

You have the right tools for the job, so use them properly and extract the potential !

Update: after elk season. I tweaked the load a bit, tried 0.5 grain lower, didn’t work. Completely stripped copper and used bore paste on the barrel, no difference.

I’ve noticed my fired headspace is longer now that I’m using the AMP by about 0.0010” which is surprising. Example I measured headspace at 2.1940-2.1945 before and now after 2nd AMP run it’s coming out fired, nearly every case at 2.1950-2.1955”. I readjusted my sizing die for a 0.0010” bump +/- 0.0005” and everything seems to have settled down.


Anyways I tweaked the load a bit more played with seating depth seating 0.0050” longer and bam it’s now back to 1/2 MOA or better hammering. Shot in 26*F weather with cold soaked ammo to verify velocity on my hunt and came up with an SD of 4.2 for a magazine, and ES of like 8… obviously a small sample size but the ammo seems to be back in the groove.

Bottom line, I should have switched to AMP with my new barrel, not midway through trying to get a load working that wasn’t the same.

 

[iceng]

Glad it worked out, and thank you for reporting back.

 

[Yondering]

I’ve noticed my fired headspace is longer now that I’m using the AMP by about 0.0010” which is surprising. Example I measured headspace at 2.1940-2.1945 before and now after 2nd AMP run it’s coming out fired, nearly every case at 2.1950-2.1955”. I readjusted my sizing die for a 0.0010” bump +/- 0.0005” and everything seems to have settled down.

This may seem like a minor quibble, but it's kind of an important detail to understand. 2.1940" is not your headspace, it's your fired shoulder datum measurement.

Headspace, rather, is the difference in base to shoulder length between your chamber (indicated by the fired brass measurement) and the sized brass. So in your example, assuming it's annealed brass and a full pressure load that forms to your chamber well, your headspace is that .001" bump. If you ignore brass springback (a reasonable assumption if the brass is well annealed), shoulder bump is headspace.

It's also worth pointing out that the shoulder datum measurement is specific to your comparator, as small changes in comparator hole size and corner shape will change that measurement, so don't try to compare it to someone else's number. It's a comparative (before and after) measurement, not an absolute measurement; that's why many of us just zero the calipers on the fired brass instead of recording the shoulder to base value. Then you can measure bump directly with no math involved.

 

[Rhed]

Do you lube the inside necks before you seat? Like Reddings dry neck lube? And do you have a concentricity gauge to check after you seat?

 

[Awesymoto]

This may seem like a minor quibble, but it's kind of an important detail to understand. 2.1940" is not your headspace, it's your fired shoulder datum measurement.

Headspace, rather, is the difference in base to shoulder length between your chamber (indicated by the fired brass measurement) and the sized brass. So in your example, assuming it's annealed brass and a full pressure load that forms to your chamber well, your headspace is that .001" bump. If you ignore brass springback (a reasonable assumption if the brass is well annealed), shoulder bump is headspace.

It's also worth pointing out that the shoulder datum measurement is specific to your comparator, as small changes in comparator hole size and corner shape will change that measurement, so don't try to compare it to someone else's number. It's a comparative (before and after) measurement, not an absolute measurement; that's why many of us just zero the calipers on the fired brass instead of recording the shoulder to base value. Then you can measure bump directly with no math involved.

I know I’m giving the datum based off a specific comparator for the cartridge, but I’m just giving numbers for numbers sake.

 

[Yondering]

I know I’m giving the datum based off a specific comparator for the cartridge, but I’m just giving numbers for numbers sake.

The point wasn't about the numbers, but about understanding what headspace is, so we can all be on the same page when we talk about it.

 

[bax]

You mentioned that seating forced is light. Since you are annealing the brass, it is softer that it was before so neck tension is less. The rounds may be more susceptible to damage from ordinary handling or abuse. For example, bullets may be set back in the magazine by recoil - stuff like that. You might want to change your button to a .332 and your mandrel to a .306 or numbers like that - aim for a .304 neck ID instead of .305.

 

[HotrRod308]

More than likely it's your neck tension that has changed... If it were me, I'd go to bushing a couple thou tighter than before and see what I got?

There's no real need to worry about overworking the brass anymore with the AMP in the mix every firing.

As an aside, I've actually been experimenting with purposely squashing my necks down more than I used to with smaller bushings before opening them back up with a mandrel... playing with the amount of engagement I want to get with the mandrel. I'm finding I can get some "free speed" without doing anything else if I want, and/or lower my SD/ES numbers by just playing with that... neat stuff.

This is exactly what I do... Crazy good results with my 6BRA.