First Crack at Load Development

[jevan23]

Nice start but you might want to consider a redo and adding more material. The point of bedding is to ensure support for the entire action within the stock. You have contact points but the sides and most of the lug is unsupported.

I would support around the barrel nut regardless.

Jerry

Ok, so round 2, i dremeled out the old bedding and re-bedded the stock. Used a lot more bedding compound this time.

 

[legi0n]

looking good.
range report?

 

[jevan23]

looking good.
range report?

Hopefully Wednesday..

 

[jevan23]

Ok, so I picked up a Hornady headspace comparator kit; according to SAAMI the chamber headspace is 1.4636 to 1.4736, and the cartridge headspace is 1.4596 to 1.4666. New unfired brass measured in at 1.458 (just under SAAMI min spec) and once fired brass measures 1.457. What gives? Why is the brass headspace below SAAMI spec and shrinking after firing?

I measured between 5 and 10 cases of both unfired and once fired lapua brass, the once fired brass had the primer removed with a lee universal decapper before measuring.

 

[legi0n]

What kind of caliper did you use?
Mine sometimes gets out-of-zero merely by getting a few particles of dust on the jaws.
Then I need to wipe the jaws clean and re-zero.

 

[jevan23]

Its a digital caliper, i zeroed it with the headspace unit attached and measured the casings. when i didn't measure what was expected, I closed the caliper on the headspace unit and it was still reading zero. I followed the directions of inserting the case into the headspace unit, closing the calipers on the case and rotate the case to ensure the the caliper is aligned with the case properly.

 

[legi0n]

If chambering the loaded cartridge went smooth and easy, it makes no sense to get shorter cases after firing.
The only things I can think of are:
- measurement error (doesn't seem to be the case)
- uneven case head on new cases that flattens out during firing (as in the primer pocket walls raised 0.001" => longer unfired case)
- different shoulder shape on the unfired brass (than your chamber has) => the gauge seats somehow longer or shorter
- fired case bumped by the decapper (very unlikely)

 

[phishroy]

There is no use wasting another shot, in trying to adjust the ammunition, in an attempt to improve the group size.
The rifle is walking the bullets. Your last group is about six inches higher than the first group.
This gives every indication that your rifle is badly in need of bedding.
The rifle should be properly bedded and not walking the bullets, before there is any use in adjusting the loads.

I think H4831 is Mostly right, that or inconsistent contact points with the rifle between shots and groups.

here is a clip that may help, its a long one but it really does simplify things that may be over analyzed about working up loads.

 

[jevan23]

If chambering the loaded cartridge went smooth and easy, it makes no sense to get shorter cases after firing.
- different shoulder shape on the unfired brass (than your chamber has) => the gauge seats somehow longer or shorter

I was thinking the chamber could be changing the shape of the shoulder as well. I cycled a new lapua case, a once fired lapua case, and a once fired hornady case through the rifle; the lapua cases had a bit more resistance when locking the bolt, but not by very much.

 

[jevan23]

I think H4831 is Mostly right, that or inconsistent contact points with the rifle between shots and groups.

here is a clip that may help, its a long one but it really does simplify things that may be over analyzed about working up loads.

Yea I started watching Rex's vids before I bought my rifle, it helped with choosing a caliber and what to look for when buying a scope as well.

 

[jevan23]

So when prepping the brass for reloading, should the order be:

1 - Remove primer
2 - Clean
3 - Body size
4 - Neck size
5 - Turn outside neck (when required)
6 - Trim to length (when required)
7 - Chamfer and deburr

thanks,

 

[legi0n]

I was thinking the chamber could be changing the shape of the shoulder as well. I cycled a new lapua case, a once fired lapua case, and a once fired hornady case through the rifle; the lapua cases had a bit more resistance when locking the bolt, but not by very much.

this could be it then: your chamber seems to be a tad shorter than the new lapua brass and when you chamber it you set the shoulder back 0.001".

 

[jevan23]

Finally got a chance to get out to the range yesterday, I loaded 5 rounds of 24.0, 24.2 and 24.4gr and tried again to see if the bedding, re-torquing action screws/scope rings made a difference.

Not including a called flier, the 24.0 group shrunk by 50%, 24.2 shrunk 30% and 24.4 grew 10%.

 

[Loyalist]

Nice. The groups shrank and your loads aren't walking like before. That was a solid improvement!

 

[jevan23]

I picked up a Redding body die and before I prep the brass for my next reloads, I want to check with you all and see if I have the steps in correct order for optimizing accuracy:

1 - Deprime brass with Lee universal deprimer (so primer pocket is open for cleaning)
2 - Clean brass with Hornady sonic cleaner
3 - Body size with Redding body die (to control head space)
4 - Outside Neck turn (to reduce neck thickness to acceptable margins and create uniform neck thickness before neck sizing)
5 - Neck size with Lee collet die
6 - Trim, chamfer and deburr with Lee hand trimmer and RCBS chamfer/deburr tool

Let me know what you think, or how you do it!

 

[jevan23]

Okay, so I thought I would try out the recommendations made earlier in the thread on some once fired Winchester brass to get all the kinks out before processing the Lapua brass. Brass has been deprimed and cleaned. The next step is to run it through the body die.

The Redding body die only touches the shoulder and top of the case. All it does is allow you to control your headspace very precisely. The base of the case is not touched ... you want to leave this area alone.

So the question now is what headspace should I want?

Unfired cases - 1.458" headspace
Once fired cases - 1.457" headspace
The assumption is that chambering the case is bumping the shoulder back 0.001" which would imply the rifle chamber headspace is 1.457" (0.007" below SAAMI).

The Lee collet neck die, Redding body die, and Forster seater is what I use and what I would recommend. You need to control the case sizing otherwise, you can create other harmonic issues with an overly tight to chamber case.

Should I set the die to give 1.457" headspace or bump the shoulder back another 0.001-.002"?

Edit:
Found a link on another site that showed Precision Shooting's Reloading guide for NRA Hi-Power competition recommends 0.002" headspace for bolt actions.

 

[jevan23]

Been a while since I last posted on this thread, I've made a few changes to my setup:

1. I've ditched the bipod and got a proper front rest for the rifle (still shooting from the bench)
2. I've switched from 69gr SMK to Hornady 68gr BTHP
3. I've spent some time behind the .22 working on technique
4. I've outside neck turned the Lapua brass, and projectiles are now able to fall through the necks of spent cases about 9 out of 10 times.


Got out to the range last night, it was about 10C out and almost no wind. I previously tried some groups of 3 with the 68gr and it really didn't tell me much, the best groups were around 23.1/23.3 so for this trip I reloaded 5 groups of 5 cartridges varying from 23.0 to 23.4gr of Varget. Below are the results after 3 fouling/bore warming shots:

Hornady 68gr BTHP / CCI Primers / Lapua Brass / Varget Powder

23.0gr - 1.176 MOA
23.1gr - 0.521 MOA
23.2gr - 1.185 MOA (The low flier was shot #3, didn't call it as a flier.. not sure what happened?)
23.3gr - 0.536 MOA
23.4gr - 0.457 MOA

Any help reading the results would be appreciated, as everything from 23.1-23.4 grouped pretty consistently.
Might be worth trying a few 10ths of a grain more powder and see where the groups start to open up?

 

[Rayleigh_Scattering]

Given that I have little skill and an un-bedded rifle, how would I look at a pattern and say "The first thing I should do is bed this thing before I waste any more ammo." or "The rifle works fine, I just need more practice."?

What are some of the clues I might look for?

 

[Mystic Precision]

Great work... bed the action properly. Tune around the 23.3 to 23.5 gr range.

Do 3X5rds of each load now... keep the barrel cool. Watch the winds. Now you are looking for the average group size - with a factory pipe, 1/2 min accuracy average is fantastic but it has to be consistent. If you can go to 200 or 300yds, it will be very obvious which one is ideal.

Watch the brass neck thickness on the Lapua stuff AND anneal every 2 to 3 firings. The bullet should fall into the neck 100% of the time. IF any case sticks, monitor and see if it tosses a flyer. That brass is very stiff and can lead to other issues.

When turning, try and cut into the shoulder a bit... that is where the donuts build and where your bullet is likely to get stuck and what can cause all manner of flyers and headaches.

Well on your way...Congrats.

Jerry

 

[jevan23]

Given that I have little skill and an un-bedded rifle, how would I look at a pattern and say "The first thing I should do is bed this thing before I waste any more ammo." or "The rifle works fine, I just need more practice."?

What are some of the clues I might look for?

From what I gathered from H4381, the rifle could use a bedding job if the rifle is 'walking' the bullets. If you look at my first group of targets, from 24.4gr-24.8gr the bullets impact is about 1" higher from the 0.4gr powder increase. In the last group of targets a 0.4gr powder increase only shifted the bullets impact about 1/2". I guess plain old experience tells you what is reasonable for a shift in impact... or maybe some fancy ballistics program..

There is no use wasting another shot, in trying to adjust the ammunition, in an attempt to improve the group size.
The rifle is walking the bullets. Your last group is about six inches higher than the first group.
This gives every indication that your rifle is badly in need of bedding.
The rifle should be properly bedded and not walking the bullets, before there is any use in adjusting the loads.