Weird load issue

[NZ_Fclass]

I suggest that you stop chasing velocity The target doesn't care what speed you shoot at. Go back to the powder load that shot the best group - H4350 only - and shoot 3 10 shot groups., 20 minutes apart. If you cannot achieve every group around a half inch, there's something else wrong with the set up.

If you have to make changes - one thing at a time - distance from the lands, neck tension, primer, even a bullet change.

It may even be worth testing a 120/123g bullet with Varget - 39.5g. It's a known accurate load for the Creedmoor and even performs well at 800 yds ( well, it did yesterday in a 20in Tikka UPR factory gun)

 

[K22]

I shoot prone on a bipod and bag. Testing is 100yds.

I don't know how you could expect any reliable test load data (shots on target) testing off a bipod in the prone position - too much chance for shooter error.

Retest on the sturdy bench with a high-quality front and rear rest.

 

[105gr]

the only other thing I can think of that might influence differences (in regard to the load itself) would be neck tension. Do you anneal before each firing?

This was definetly an issue. I fixed the issue and anneal every firing now. More test loads on deck.

 

[105gr]

Are you cleaning to bare metal bore and than shooting groups with no foulers? Easy checks, try a different primer. If same results change one step in your brass prep at a time. 1. Don't anneal a batch 2. No tumble(wipe case clean)with light neck brushing.
If you don't configure a testing method to isolate what you are doing during the loading process to cause the results you are seeing(you don't believe it is a rifle or shooter issue) you're just guessing at the fix.

I am shooting a fouled barrel every time. If it was a clean barrel I fire some factory till it straitens up. Normally only 1 or 2 shots is all it takes.

 

[105gr]

The first thing I did when I started shooting my 6.5 CM was get rid of the Hornady brass.

I have some Peterson ready I just have alot of Hornady so I wanted to do testing with cheaper brass

 

[105gr]

How do you seat primers?

RCBS hand seater

 

[105gr]

Go back to the powder load that shot the best group

Thats what I did. The best groups also have the best ES. When I try to load for that group it doesn't repeat that load

 

[mgunderson]

I am shooting a fouled barrel every time. If it was a clean barrel I fire some factory till it straitens up. Normally only 1 or 2 shots is all it takes.

I suggest to stop mixing factory and reloads. Some Powders do not play well together.

Is the factory ammo good enough to use for a seating depth test? Similar bullet to what you are reloading. It can be a good Check of other issues.

 

[6.5 forever]

I have some Peterson ready I just have alot of Hornady so I wanted to do testing with cheaper brass

Wasting other components solves nothing But it's your choice.

 

[105gr]

Wasting other components solves nothing But it's your choice.

I know. I need to stop being cheap and get serious. I just wanted an idea of what the gun was doing. Now I have an idea. Now I can improve.

 

[105gr]

I suggest to stop mixing factory and reloads. Some Powders do not play well together.

Is the factory ammo good enough to use for a seating depth test? Similar bullet to what you are reloading. It can be a good Check of other issues.

Its factory 140ELD. Same brass same bullets. I'm glad you brought that up. Does Hornady put a crimp on their match ammo? Can I just seat it deeper in .003" increments?

 

[105gr]

Your window picker might be broken.

What do you see?

 

[foxguy]

Deprime. Tumble. Anneal. Tumble. Resize. Trim. Prime. Charge. Seat.

I use the Hornady headspace comparitor and use brand new brass as "zero". Measure fired brass and some get as big as .004" bigger than new brass. I set the die so sized brass is set back to zero. Measure seating with the bullet/cartridge comparitor.

I'm thinking you may want to just Bump the shoulders back .002( from the fired case size). It's a Bolt Action, bump them back .002 and see if the resized case chambers easily and the bolt closes easily. head space and Ignition is important.

 

[Sniperhandle]

OAL of the brass may be a factor. If some are too long, it will cause all sorts of mayhem.

Regards
Rick

This^^^^^^

A long time ago I had a chamber that was just enough too short in the neck that it crimped the bullet when closing the bolt, It would have velocities all over the place and you would get 2 bullets in the same hole and then one way over to one side or the other. The reamer was not in spec in the neck. I trimmed the brass a lot, I don't remember how much but it was quite a bit to solve the issue, Shot small after that. Not saying this is your problem, But it's something to check.

I know it's hard when you ask a question on an internet forum you will get a hundred different responses and it's hard to wade through them. You will figure it out. I wouldn't obsess so much over the velocities. If you had a tuner it would be different, Then you could find the speed you want before you hit pressure and then start tuning.

 

[105gr]

This^^^^^^

A long time ago I had a chamber that was just enough too short in the neck that it crimped the bullet when closing the bolt, It would have velocities all over the place and you would get 2 bullets in the same hole and then one way over to one side or the other. The reamer was not in spec in the neck. I trimmed the brass a lot, I don't remember how much but it was quite a bit to solve the issue, Shot small after that. Not saying this is your problem, But it's something to check.

I know it's hard when you ask a question on an internet forum you will get a hundred different responses and it's hard to wade through them. You will figure it out. I wouldn't obsess so much over the velocities. If you had a tuner it would be different, Then you could find the speed you want before you hit pressure and then start tuning.

Two things.
1) I started trimming .005" under trim length to make sure this was not an issue.
2) I have a tuner. An EC tuner brake. I havent messed with it yet because I wanted to figure this problem out first.

 

[Sniperhandle]

Two things.
1) I started trimming .005" under trim length to make sure this was not an issue.
2) I have a tuner. An EC tuner brake. I havent messed with it yet because I wanted to figure this problem out first.

The problem I had was way too short of neck, I had to take like 40 or 50 thou off. The reamer was what caused the problem, Not the brass, The easiest way for me to solve the issue was to shorten the brass.

 

[jelenko]

Before working on this load development, have you found other loads that shot consistently from prone with the bipod? I know some people can get pretty good with them, but they are very easy to produce large, inconsistent groups.

Other than the cases being marginal on length [i.e., some are getting wedged by the end of the chamber], I don't think there is anything that's going to produce a 100 fps difference than powder charge.
So, if it were me, I'd confirm my resized cases easily drop into the chamber and the bolt closes easily. I'd do that as a screen for all the cases for the next steps.
I'd want to absolutely confirm that the velocity is varying by 100 fps. I'd redo a portion of my ladder - choosing the powder charges to cover two of the loads that looked good the first time - like 5 to 6 powder increments. I would be meticulous to ensure each set of rounds with the same powder charge were in a separate baggie with a piece of paper that captures the load data BEFORE I loaded the next set of rounds.
A corollary: DO NOT put all of the rounds into the same cartridge holder.

Now, I would redo the ladder. Once again, meticulously ensuring that the powder charge of the rounds corresponds to the powder charge written on the target.

Pick a load that looks good.

Load 20 rounds with that charge [recognizing that I might not need all 20].
Fire one round at a time checking the chrono on each shot. I would fire 10 to see the es and sd along with the average.

If I had done the above steps, I would expect the velocities to be very close to those when I picked the charge [I know, of course, duh]. My objective would be to either confirm that the velocities were close to the group in the ladder, or, if not I would pull a few bullets and reweigh the charges.

Again, if it were me, I would want to test for accuracy from a position in which I had lots and lots of experience shooting small groups.

 

[mgunderson]

Its factory 140ELD. Same brass same bullets. I'm glad you brought that up. Does Hornady put a crimp on their match ammo? Can I just seat it deeper in .003" increments?

Yes!

 

[243winxb]

I use the Hornady headspace comparitor and use brand new brass as "zero". Measure fired brass and some get as big as .004" bigger than new brass. I set the die so sized brass is set back to zero. .

Do Not set the shoulder back to unfired factory brass. When closing the bolt on your Rem 700, go for a crush fit.

Measure the head to datum of the crush fit brass. Size no more.

Case volume changes from factory to fired brass. This change in volume has an effect on pressure/velocity.


The little 223 has a case volume change of 4% when comparing factory to fired brass.
https://discover.dtic.mil/

 

[Kracken McGraw]

Its factory 140ELD. Same brass same bullets. I'm glad you brought that up. Does Hornady put a crimp on their match ammo? Can I just seat it deeper in .003" increments?

I imagine there is some sort of crimp on the factory bras since they don’t chamfer or deburr the new cases. The new cases had to have the neck expanded a 1/16 or so deep to allow the bullet to be seated, then they push this expansion back in after seating the bullet.