Reloading Newbie velocity issues

[10mmg]

I am reloading 6.5 creedmore with 129 nosler accubond LR with once fired nosler brass. Following the nosler book I am using fed 210 primers and RL15. My dad is trying to reload 7mm weatherby magnum using h4350 and 154 hornady. Both of us are using rcbs dies. Powder measure has been verified digitally and on a manual scale.

The issue is this. Our FPS is swinging all over the place. Sometimes as much as 125 fps. The chrono has been verified using factory nosler ammo. The factory stuff has a 7-9fps variation. The brass is cleaned and the primer pockets cleaned.

So my question is what could be causing the variation? Dad and I are using the same press. Any thought or ideas would be greatly appreciated as I dont want to keep wasting ammo.

Thanks

[h20hunter]

How uniformly accurate is your seating depth? To far from or to tight to the lands may be an issue if your seating depth is not consistent.  I'm no expert so just a thought. Neck tension maybe....to much or to little?

[buckfvr]

Variance of 125fps "to me" indicates a powder charge issue.  Until you can consistently get fps under control, I would weigh each charge individually on a small digital scale after calibrating it.  Load 5, fire and confirm.

If using standard dies and basic reloading technique neck tension should all be the same and unless you have a loose seating stem, seating depth should be uniform enough.

Also, Im assuming you are not mixing brass........

[hunter399]

Something isn't consistent.
What does accuracy look like.
Can't imagine too good.

[mountainman]

Variance of 125fps "to me" indicates a powder charge issue.  Until you can consistently get fps under control, I would weigh each charge individually on a small digital scale after calibrating it.  Load 5, fire and confirm.

If using standard dies and basic reloading technique neck tension should all be the same and unless you have a loose seating stem, seating depth should be uniform enough.

Also, Im assuming you are not mixing brass........

This👆👆

[Rainier10]

Tag so I can see what the final fix is.

[bobcat]

Can you give us an example of what your actual velocity variation is? Because if it's more like 20 or 30 fps from shot to shot normally, that's entirely different than a 125 fps difference every time.

Are you cleaning the brass? Tumbling? If so, before resizing or after? Or both? What are you using for lube when you resize?

[GWP]

Factory ammo is new bulk ‘everything’ and ‘should’ be loaded to very close tolerances.
Your fired cases have conformed to your chamber and are slightly harder than they were from brand new. They have also stretched in length slightly.
Are you neck sizing only? You may be resizing too much.
There are many things to get to extreme tight FPS and accuracy that any one item may throw it off.
As someone stated, how is the accuracy? That is really all that matters if you are shooting at speeds that will reliably cause the bullet to perform as it should.
Be ‘realistic’ about the distance you are shooting, and capable of shooting.
Eliminating competition shooters, I have seen ‘maybe’ three shooters that were ‘actually’ capable of shooting truly long distances that they boasted about. Two were snipers in the military, so I would probably put them in with the competition shooters.
You can start chasing being ‘exact’, and while it can be fun, if it really does not matter to the accuracy, it may not be worth your time or worrying about.

[callturner]

Are you copying the load fps the same as your factory loads ? I shoot one hole with IMR 4350. @ 100 yds. I also shoot Nosler brass.

[b23]

It is very possible, even likely, it's not just one big issue but rather 2 or 3 smaller issues. 

Depending on case size I've found inconsistent seating depth, particularly when you start getting close to the lands, to cause bigger ES numbers than being a slight bit off on powder charge.  Are you using a bullet comparator on your calipers or just measuring base to tip?  If you aren't using a bullet comparator you need to get one because measuring base to tip isn't a very accurate way to do it.

Also, how are you measuring your cases for sizing?  Again, get yourself a headspace comparator and start measuring your cases to shoulder datum and not just for overall length.  A loaded cartridge is essentially a pressure chamber and any change in the size of that pressure chamber will cause changes in the pressure curve which will result in velocity changes.

Another thing that's worth mentioning, make sure your primers aren't sitting proud or slightly raised when you measure any case with a primer in it because that'll wreak havoc with your numbers when you're measuring.

Making everything about your ammo as consistent as possible from round to round is what you're after.

[buckfvr]

He states "Reloading Newbie"......its most likely a simple problem.

[jrebel]

Two many variables and not enough information.  I would highly recommend finding and experienced re-loader close to you, and pick their brain one on one.  Lots of good advise on here but also a lot of assumptions based on the limited info.  It is likely an easy fix....if we could see your exact process. 

I will take a few stabs at possible problems...
1.  Mixed head stamp brass could could be the easy fix.  Make sure you are not shooting multiple head stamps
2.  Powder drop is not consistent, though 125 fps would indicate more then a couple tenths of a grain difference....usually
3.  Seating depth, though again, I wouldn't expect to see a spread in velocity of 125 fps if all are being seated with the same seating die. 
4.  If your full length sizing, your neck tension should be close.  The brass won't stretch enough in one firing to cause an issue in most cases, especially if they were factory to begin with. 


So.....the most likely culprits in my opinion are;  1.  You are not on a node and you are getting big fluctuations...combined with 2.  You are shooting to fast, not allowing your barrel to cool and seeing faster speeds with 3, 4, 5, etc. shots.....combined with 3.  your powder drop being slightly inconsistent (this is very normal for the standard powder drops as they can very 2-3 tenths either way with certain extruded powders. 

How did you go about finding the powder charge you ended on?  Did you ladder test....or use another method to find a node? 

Again, lots of variables....find an experienced reloader close and they will get you dialed.   

[10mmg]

How uniformly accurate is your seating depth? To far from or to tight to the lands may be an issue if your seating depth is not consistent.  I'm no expert so just a thought. Neck tension maybe....to much or to little?

I measure the over all length of the factory loads vs my reloads and they are all within .001. The factory loads use the same bullet and weight as my reloads.

[10mmg]

Variance of 125fps "to me" indicates a powder charge issue.  Until you can consistently get fps under control, I would weigh each charge individually on a small digital scale after calibrating it.  Load 5, fire and confirm.

If using standard dies and basic reloading technique neck tension should all be the same and unless you have a loose seating stem, seating depth should be uniform enough.

Also, Im assuming you are not mixing brass........

Brass is all nosler the 125 is across a 5 shot string with the average fluctuations being 25-50 fps round to round.

[zwickeyman]

You could also try the H4350, should work well for you in the CM. I use IMR4350 in mine with an ES of 15