Lack of annealing and velocity

[Gil P.]

I don't anneal, and am wondering what effect it has on velocity. I bring this up because get very inconsistent speeds on my ammo.
I load using the same components, powder, and charge weight. Some days I get velocities around 2900 from all my ammo loaded that day, other days I get 2825 from my ammo loaded in a different day.
Maybe it's my scale?

6.5x47, 140 hybrid, cci 450, 40.5 gr H4350 same box of Lapua brass, .002 neck tension.

 

[RegionRat]

First a question.

Are those velocities from one loading batch on different days? Or...

Different loading batches on different days?

Are you shooting a large number of rounds per session and cleaning in between sessions?

Describe how much you are shooting and cleaning between sessions and how many rounds you use to foul or how many it takes to settle it down?

 

[Gil P.]

Different loading batches from different days.

40 - 70 rounds per session, cleaning between each session, (and therefore batch of loaded ammo).

2 rounds to foul.

 

[RegionRat]

I don't need to say it because I am sure you already know.

To find out, you will have to isolate changes and test one at a time.

That means, load a larger batch for the next trip and randomize the rounds in case there is a trend from front to back within the batch. That way the differences within a batch are as evenly distributed as you can make them.

Split that batch into two to three session worth. If you can shoot these sessions within two to three consecutive days it would be the best. If you can't shoot them soon enough between sessions, then split one day into two sessions by cleaning in between the two halves. Take your data on every shot.

We expect to learn two things per session:1) are more fouling rounds required before taking data, and 2) what are the stats for speed telling us?

Clean in the same way you do between the previous sessions.

Then... Shoot again.

If the ammo is all from the same batch, the effect of cycles on neck tension and case volume, charge weight errors, etc., are minimized.

If cleaning is the cause, you will see a strong effect again. If there was a problem with charge weights, you will not see those averages shift since you blended and randomized the whole batch.

In seeing your averages shift, is there a change in the SD and ES? Remember, you need about 15 rounds in the statistic to get some confidence in the SD and ES.

The challenge is that sometimes neck tension and bonding can cause such huge variations that you can't ignore it. Storage time, case cleaning, firing cycles, etc., can all have an effect.

When we are on a narrow node, all of this matters.

When you are done with that first test of two closely spaced sessions, if you have a third of that same batch, I would also test them after several weeks. This tells us if bonding plays a role.

 

[Gil P.]

SD varies from 8 to 11, I haven't recorded ES. I don't think bonding is the culprit since I shoot all my batches either the same day I load them, or the very next day.

I think you are into something with the fouling, I'll monitor it closely. This barrel has been troublesome from the beginning. Getting this thing to group has been a chore.

Thank you for the advice, im definitely going to take it.

 

[KMart]

Keep track of the temperature when/while you are shooting. Variation in temperature will change the velocity, even though H4350 is suppose to be temperature insensitive. Morning versus afternoon shooting could be the culprit.
Also, testing seating depth will give variation with all other things constant.

 

[MikeMcCasland]

I don't think annealing is going to do anything for velocity variation that wide. It's either environmental variation, or some other aspect of your load/components etc.

Could also be your barrel speeding up or slowing down depending on where you are in it's life.

 

[Martin52]

I.......other days I get 2825 from my ammo loaded in a different day.
Maybe it's my scale?

Could be....what are you using ?

 

[Gil P.]

Keep track of the temperature when/while you are shooting. Variation in temperature will change the velocity, even though H4350 is suppose to be temperature insensitive. Morning versus afternoon shooting could be the culprit.
Also, testing seating depth will give variation with all other things constant.

The temperature wasn't very different, not more than 10 degrees difference. The barrel has about 500 rounds on it.

 

[Gil P.]

Could be....what are you using ?

A Lyman gen 5. I did double check it on am RCBS 505, and it was accurate to two tenths of a grain. I didn't double check it for every session though, so it could still be the culprit. I ordered an fx120i, it'll be here next week.

 

[JimSC]

in my limited experience I have found that the powder chosen along with the load weight and primer brand/type determines velocity consistency. I can say that H4350 is extremely temperature friendly. I tested a load for my 6 Creedmoor last March in the low 40's F weather and put the gun in the safe for a few months. Last Tuesday I pulled it out and the same load was within 5 FPS when shot at 90F. My guess is that you need to work on finding the right charge weight or try a different primer. Even a inconsistency on how hard your hold is between shots can cause velocity inconsistency

A lot of factors come into play in this game, both with equipment and personal technique. If expensive gear is all it took to be a success we would all just buy $2000 dollar scales and $300 dies and shoot in the zeros a few times get bored and go home and watch TV sports

On the annealing I went from the plumbers torch for years to using a annealing machine for a couple of years to no annealing at all and have seen no difference at all in anything

 

[Evan]

Do you keep your brass sorted by number of firings? Is everything you fire in a session on the same number of reloads? I don't think annealing is your problem. Many shooters have shot very very small without ever annealing.

I'd chase down your reloading process. If your loads are near max then 0.2gns is a lot of error. If your loads are backed off max, then that may not be a huge problem. Are you calibrating your scale before every reloading session with the same calibration weights? Do you notice drift, usually in the form of having to constantly rezero the scale?

 

[Leeman]

What chronograph are you using?

If it's got sky screens then you are likely to get different velocities depending on the light conditions of the day, or at least I pretty much always have. I don't worry about the absolute values, just the differences between sample batches. You would need to keep a few rounds from the different days loadings to try together on one day and see how close the speed is between batches. Also could try taking a rimfire along and firing a few rounds through the chrono to check how much variation there is on different days.

 

[JimSC]

tested some ammo back in March using virgin Alpha cases in 40 F temps. tested Tuesday temp was in the low 90's and the brass is on the 5th reload. 6.0 Creedmoor, 37.50 grains of H4350 powder, 107 SMK, Rem 9 1/2 primer. Avg FPS was 6 fps higher than in March with a 8FPS SD and a 17FPS ES. The cases have always been FL resized and have never been annealed since they left the factory. Oddly enough the ES/SD had improved a couple of digits with 5 firings on the cases and a few more rounds down the barrel

 

[Gil P.]

Do you keep your brass sorted by number of firings? Is everything you fire in a session on the same number of reloads? I don't think annealing is your problem. Many shooters have shot very very small without ever annealing.

I'd chase down your reloading process. If your loads are near max then 0.2gns is a lot of error. If your loads are backed off max, then that may not be a huge problem. Are you calibrating your scale before every reloading session with the same calibration weights? Do you notice drift, usually in the form of having to constantly rezero the scale?

All brass is the same lot, same number of firings. I calibrate the scale every time, and I recalibrate it when it starts to drift. I don't just re zero when it drifts, I recalibrate..

 

[Gil P.]

What chronograph are you using?

If it's got sky screens then you are likely to get different velocities depending on the light conditions of the day, or at least I pretty much always have. I don't worry about the absolute values, just the differences between sample batches. You would need to keep a few rounds from the different days loadings to try together on one day and see how close the speed is between batches. Also could try taking a rimfire along and firing a few rounds through the chrono to check how much variation there is on different days.

I'm using a magnetospeed, so no skyscreens. I don't think the magnetospeed is giving me errors, since I verify the velocity on an 800 yard target.

 

[Gil P.]

I kept one of my loading rounds that was giving me a velocity of 2900 fps with a supposed charge weight of 40.5 gr of H4350. I kept it in anticipation of getting the fx120i scale that will arrive on Sept 3. I measured all my loads that day on my Lyman autotrickler, and double checked it on my RCBS 505 scale. When I get the new scale I can rule out the old scale being messed up.
Otherwise I plan on checking the velocities on a fouled and clean barrel, then changing primers.

 

[Evan]

All brass is the same lot, same number of firings. I calibrate the scale every time, and I recalibrate it when it starts to drift. I don't just re zero when it drifts, I recalibrate..

Probably overkill. I'll be interested to know if the fx120 fixes this, or if there is something else causing issues.

 

[Gil P.]

I'll start testing this weekend.

 

[piie]

I don't anneal, and am wondering what effect it has on velocity. I bring this up because get very inconsistent speeds on my ammo.
I load using the same components, powder, and charge weight. Some days I get velocities around 2900 from all my ammo loaded that day, other days I get 2825 from my ammo loaded in a different day.
Maybe it's my scale?

6.5x47, 140 hybrid, cci 450, 40.5 gr H4350 same box of Lapua brass, .002 neck tension.

What are your targets telling you? Can you see a vertical drop on the targets between batches?