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Topic: Annealing and velocity variance  (Read 825 times) previous topic - next topic

Annealing and velocity variance

Question #1: how much can annealing or not annealing affect velocity? I have some Hornady brass that has been fired 8 times, necks turned, neck sized with a Forster bushing bump neck die and never reannealed. After I resize with the bushing bump neck die I do have consistent outside neck measurements but when seating bullets I can definitely tell a difference in the amount of force needed to seat bullets. Question # 2: since I have consistent neck tension is the difference in force needed to seat bullets that I'm feeling coming from differences in the hardness of the case necks from not being annealed which makes them harder or easier to stretch in order to seat the bullet? (I hope what I'm tying to say there makes sense...) I just got a Magnetospeed and started working up a new load that I think will be a good one but my extreme spread is still 34 with an SD of 9. The average velocity is 2735 fps which is exactly what I expected it to be. I started with a 0.3 gr increase in charge weight until I found a flat spot then worked through the flat spot 0.1 gr at a time from 40.9 gr to 41.7 gr. 41.0 gr shot 2733, 41.1 shot 2374 and 41.2 shot 2736. I loaded 41.1 gr H4350 behind 140 gr Barnes match burners and shot a ten round string and got the ES and SD stated earlier. On the bright side the 10 round group measured 0.858. Not the best but I shot it super fast and didn't put much effort into shooting a good group because I was more concerned with the velocity.... and getting out of the wind, rain and lightning I was shooting in... that being said I can pretty much claim those two flyers as my fault.

Re: Annealing and velocity variance

Reply #1
I seem to be chasing my tail with  annealing as  its giving great figures but poorer results. I started on 41.8 gn in 26" barrel speed 2750' 5 thou off with 147 eld m's. The group at 150m is .874. Will try on or in the lands and 10 off and see where that leads.

Re: Annealing and velocity variance

Reply #2
@Concentric so you're seeing better ES and SD #s but worse groups? What were your ES and SD #s like prior to starting annealing? I have one load with IMR 4350 and one load with h4350 that both when shooting a 10-round string the average velocity is exactly what I expect it to be however my extreme spread will be up around 35 FPS. I'm hoping that when I begin annealing those 10 round string extreme spread numbers come down to around 10 or below but I feel like that's a pretty large gap to cover just from annealing.

Re: Annealing and velocity variance

Reply #3
Dioforo previous my es for 5 shot groups was 18 to 25. Cases had been fired 5 times. There always seemed to be one wayward shot that could have made the es better.
Just shot .9015" at 150m on the lands. Vertical is much better.

Re: Annealing and velocity variance

Reply #4
dloforo annealing will give you more consistent neck tension... as brass work hardens it makes it harder to seat the bullet because it isn't stretching the case mouth as easy giving you more bullet grip... if you feel a difference in the force it takes to seat a bullet it will show up on the target and the chrono numbers.. a sd of 9 for a 10 shot string isn't horrible but it could be a little better... and I think if you annealed your cases it would improve them numbers... or toss them and start with new if their not shooting well enough... concentric be carefull kissing the lands... in my opinion that's not a very good idea and I think your results on target will worsen... the variance in bullet length will have some touching and some not and some jammed a little... causing eratic results... if you want them in the lands jam them in there a little and back off on your powder because jamming them will increase pressure...
Grant

Re: Annealing and velocity variance

Reply #5
^^^^ Good advice ^^^^ as usual from Grant. Especially on the seating depth. Seating depth should be the second thing you test for immediately after finding a safe powder charge range to test in. Without finding your optimum seating depth you're just guessing and hoping to get lucky.

Dave

Re: Annealing and velocity variance

Reply #6
@gman47564 I have an Annealeez that should show up Monday or Tuesday. I should be using the Tempilaq 750 correct not the 650? You think after I anneal those cases I should feel less variation in the force necessary to seat bullets and also hopefully close up my ES numbers a little?

Re: Annealing and velocity variance

Reply #7
I do think that. It will help for sure. I use the annealeez too and it does a fine job. I have never used the tempilaq but the 750 is what people use. I run mine till the first hint of them turning orange .
Grant

Re: Annealing and velocity variance

Reply #8
Thanks gman. Will start again with the lower load which looked promising.

Re: Annealing and velocity variance

Reply #9
I do think that. It will help for sure. I use the annealeez too and it does a fine job. I have never used the tempilaq but the 750 is what people use. I run mine till the first hint of them turning orange .

This is the way I do it also. I find it very effective.
Dave

Re: Annealing and velocity variance

Reply #10
Dloforo

Your situation sounds very much like what I went through some time back after I switched to a Forster BBND. I am not blaming the BBND or the use of one. I shoot PRS type stuff and my brass gets ejected all over the place, not taken out and put back in the box like a bench rest guy might be able to do. I believe that my necks were getting dinged up enough that the bushing wasn't making them perfectly round inside anymore and caused bullet seating pressure inconsistencies. Initially I wasn't giving it much thought and pressed on (pun intended) with my methods. One day while loading up a hundred rounds for a match I was having a heck of a time with seating pressures and I noticed that I had a lot copper shavings from the bullets laying on my press. I knew something wasn't right.

I spoke with a good friend of mine who is an old timer and been reloading and wildcatting cartridges since I was knee high to a grasshopper. He said that the necks must be digging into the bullets and causing the shavings. He suggested I go back to full length sizing. This would allow the expander ball to push any deformities and imperfections to the outside of the neck where it wouldn't affect the bullet sliding into the brass. Of course I didn't want to FLS so I grabbed a mandrel from the Sinclair neck turning kit and ran some necks across it. Guess what? Yep, all my inconsistencies were gone. Seating pressure felt the same for all the bullets I loaded. I was happy he helped me solve that mystery, but was disappointed that I couldn't see the forest through the trees.

I have since put a Lyman carbide expander ball kit in my BBND and pull it back through the necks to remove any deformities that occur during: ejection, transportation, tumbling while cleaning or removing SS media after cleaning. Some ask why I don't FLS if I am doing this? Fair enough question. The BBND bumps my shoulder back .001" and doesn't resize the body. There is less stretching and compressing of the brass, plus it leaves a slightly larger internal volume for powder. But mainly it is the fact that my brass is sized for my chamber and the brass is worked less. My brass has always been annealed every firing so that wasn't a contributor.

I would try one of the things I have mentioned above to see if that might be what is happening with your brass. It's a very easy process to troubleshoot and well worth your time to figure out what is causing your inconsistencies.
RPR 6.5 Creedmoor
Bergara 6 Creedmoor

Re: Annealing and velocity variance

Reply #11
Thank you for the input and your assistance @gman47564 @MLN1963 @6.5savageguy

Re: Annealing and velocity variance

Reply #12
Keep us informed of your progress dloforo.
RPR 6.5 Creedmoor
Bergara 6 Creedmoor

Re: Annealing and velocity variance

Reply #13
@MLN1963 I finally have some progress to report.... And of course some more questions to go with it! So my previous extreme spread was 34 and standard deviation was 9 on a 10 shot string prior to annealing. Today I shot a 20 round string with annealed cases with an extreme spread of 24 and an SD of 5 and when seating bullets I felt much more consistent pressure and didn't have any copper shavings around the case necks from the bullets. Needless to say I was happy to cut the SD in 1/2 and 10 feet per second off my ES with twice as many rounds fired but would still like to have my ES in the teens. However each time I Chrono rounds the first round fired seems to be 15 FPS faster than the average of the string which would absolutely be the difference between teens and 20s on ES. Is this just because of a cold bore and once the barrel warms up it swells and constricts the bullet a little? Also about 1/2 of my brass showed a ring around the circumference of the case 1/2 an inch above the case head and I could clearly feel the indentation from the attempted separation with a paperclip inside the case. These are the first cases I've ever had do that and they're also the first cases that I've ever annealed. The cases showed no other  pressure signs and I have shot the same  load  a lot  with the same brass  without pressure signs. I used 750 degree Tempilaq inside the case mouths but did not have any 450 degree to run down the case body. I had my flame right at the neck/shoulder junction and the Tempilaq  inside the case mounths was melting with the cases in the flame for approximately 3.9 or 4 seconds with no change in the color of the flame of other signs of over annealing. These cases have been fired approximately 8 times prior to being annealed so I'm wondering if my case body got too hot too far down weakening the body around the web or if these cases were just at the end of their life span? Any guesses at that?

Re: Annealing and velocity variance

Reply #14
I always run 3-4 foulers to warm the barrel before any testing. You have already figured out why.

The case head separating issue sounds like you are bumping your shoulder back too far. I strive for .001”-.0015” on my brass.
RPR 6.5 Creedmoor
Bergara 6 Creedmoor