Load issue

[kriller134]

First time I’ve had an issue with my load this past weekend. Load jumped up a solid 100 FPS. I thought it could be a different lot of powder but that seems excessive. The rounds have been sitting for a couple months, so idk if that makes a difference or not. I’ve read somewhere that it could be a neck tension issue with the bullet fusing to the neck? Any insight will be helpful thanks.
142 smk
42.6gn rl16
.030” off lands

 

[mudpig]

Check for a carbon ring in the chamber.....that one bit me once!

 

[kriller134]

Check for a carbon ring in the chamber.....that one bit me once!

I forgot to mention that I did check for a carbon ring and it’s clean.

 

[nn8734]

Do you check / monitor for neck tension each time you load up a batch?

Have you changed anything in your production process (new dies, powder thrower, case lube used etc)? We’re your MV measurements taken previously and this most recent +100 fps batch from the same shooting location and roughly similar conditions?

how many rounds did you chrono and what were the velocities? SD/ES? Difference in SD/ES between this last batch and previous batch?

Rounds sitting for a couple months won’t change or be any different from when first produced unless they were not stored in a room temp, dry location. Were they?

Carbon ring does seem like a good explanation but could be other things.

ETA - if you use a charge master or other electronic scale, do you occasionally compare thrown charges between the two to confirm they align?

Once I discovered my Lyman gen6 was under throwing by .3-.4 grains compare to two of my charge masters and it just needed recalibration. Just throwing it out there as another possibility, esp if your MV is consistent ~100 fps faster round over round all of the sudden compared to all your other data taken previously.

 

[spife7980]

I forgot to mention that I did check for a carbon ring and it’s clean.

Clean it again anyways

If you know that the ammo didnt change then its gonna be the barrel.

 

[kriller134]

Do you check / monitor for neck tension each time you load up a batch?

Have you changed anything in your production process (new dies, powder thrower, case lube used etc)? We’re your MV measurements taken previously and this most recent +100 fps batch from the same shooting location and roughly similar conditions?

how many rounds did you chrono and what were the velocities? SD/ES? Difference in SD/ES between this last batch and previous batch?

Rounds sitting for a couple months won’t change or be any different from when first produced unless they were not stored in a room temp, dry location. Were they?

Carbon ring does seem like a good explanation but could be other things.

ETA - if you use a charge master or other electronic scale, do you occasionally compare thrown charges between the two to confirm they align?

Once I discovered my Lyman gen6 was under throwing by .3-.4 grains compare to two of my charge masters and it just needed recalibration. Just throwing it out there as another possibility, esp if your MV is consistent ~100 fps faster round over round all of the sudden compared to all your other data taken previously.

I didn’t change any of my reloading practices. It normally shoots right around 2850-60. This weekend it was shooting 2950ish. My sd/es didn’t change much over the 10 rounds I chrono on a lab radar. I’m just so confused why this is happening out of nowhere.

 

[918v]

Cold welding

 

[kriller134]

Cold welding

Can you expand on this please?

 

[XLR308]

Can you expand on this please?

If you have any of the same ammo left put it in your seater die and seat it .005-.010" deeper.
If it doesnt move smooth and easilly it has cold welded in the neck.
Then take that same ammo and run it over the chrono.

 

[nn8734]

If you have any of the same ammo left put it in your seater die and seat it .005-.010" deeper.
If it doesnt move smooth and easilly it has cold welded in the neck.
Then take that same ammo and run it over the chrono.

What typically causes cold welding?

 

[orkan]

Interesting timing on these posts. I literally just did some "cold welding" science.

Fun little experiment with 22BR

Pulled out my 22BR for some low level science yesterday. I had been wanting to do a "shelf stability" test on some ammo and a "bore condition" test on a rifle stored vertically with a suppressor on it... so I haven't fired this rifle in nearly 3 years. I loaded the ammo back then, and shelved it...

www.snipershide.com

 

[XLR308]

What typically causes cold welding?

It came up in a thread awhile back and i did a little experimenting for my own cuiosity.
I pulled some bullets from 1970's production 30-30 win ammo that wasnt in very good condition and some 300Wm ammo i had that had been loaded for years.
Niether had any issues but it was explained to me that one the factory ammo may have had some type of sealent and the reloaded 300wm ammo had carbon in the neck that acted as a lubricant.
I have been lubing the necks on my reloads now for years with no issue (lubing the inside of necks or a turning arbor in expander die) but when i first built my 6.5CM i took a new piece of lapua brass and seated a 147eldm in it for a dummy round.
It seated fairly easy but a couple years later when i pulled it i thought it was going to pull the rim of the case out of the shell holder.
It was a new clean case no carbon or any other lubricant, neck tension was probably excessive as it was new and untouched other than a load chamfer and when it did let go it popped like it had been glued into the neck.

 

[nn8734]

It came up in a thread awhile back and i did a little experimenting for my own cuiosity.
I pulled some bullets from 1970's production 30-30 win ammo that wasnt in very good condition and some 300Wm ammo i had that had been loaded for years.
Niether had any issues but it was explained to me that one the factory ammo may have had some type of sealent and the reloaded 300wm ammo had carbon in the neck that acted as a lubricant.
I have been lubing the necks on my reloads now for years with no issue (lubing the inside of necks or a turning arbor in expander die) but when i first built my 6.5CM i took a new piece of lapua brass and seated a 147eldm in it for a dummy round.
It seated fairly easy but a couple years later when i pulled it i thought it was going to pull the rim of the case out of the shell holder.
It was a new clean case no carbon or any other lubricant, neck tension was probably excessive as it was new and untouched other than a load chamfer and when it did let go it popped like it had been glued into the neck.

Interesting, tbh I’ve never heard of it before. Did a qnd web search and read threads where some folks using graphite on their bullet bases to prevent cold welds.

I lightly lube the bases of my 5.56 bullets with Hornady One Shot before seating them; before doing that, some bullets would actually collapse the case neck going in.

All my rounds have .002” neck tension but even with that an occasional .223 bullet would go in real stiff or collapse the neck. Since lubing the bullet base, I’ve never had that issue. From what MV data I’ve gathered across my small frames since doing this I haven’t noticed any effect on loads’ performance.

May start doing the same to all my other stuff.

 

[kriller134]

It came up in a thread awhile back and i did a little experimenting for my own cuiosity.
I pulled some bullets from 1970's production 30-30 win ammo that wasnt in very good condition and some 300Wm ammo i had that had been loaded for years.
Niether had any issues but it was explained to me that one the factory ammo may have had some type of sealent and the reloaded 300wm ammo had carbon in the neck that acted as a lubricant.
I have been lubing the necks on my reloads now for years with no issue (lubing the inside of necks or a turning arbor in expander die) but when i first built my 6.5CM i took a new piece of lapua brass and seated a 147eldm in it for a dummy round.
It seated fairly easy but a couple years later when i pulled it i thought it was going to pull the rim of the case out of the shell holder.
It was a new clean case no carbon or any other lubricant, neck tension was probably excessive as it was new and untouched other than a load chamfer and when it did let go it popped like it had been glued into the neck.

I’m leaning towards it being cold welded. I remember that batch I had wet tumbled longer than I usually do. I’m thinking it took off all of the carbon on the inside of the necks. I’m going to load up more for a match this weekend without changing my loading practice and see what I come up with.

 

[918v]

If you stick the rounds back in the seating die and try to seat them deeper and the bullets make a popping sound or feel like a pop than they are cold welded.