Load development for extreme accuracy, Need input

[leoestby]

Hi. I'm have been reloading for my factory rifle for 2 years, and have god understanding of basic reloading.

Now I have ordered a custom rifle chambered in 7WSM (0,316" Tight neck 0,190" freebore) with a 26" Krieger barrel and a suppressor. And I want to find best accuracy without shooting several hundred rounds. It will be used as a long range rifle. Bullets will <span style="text-decoration: underline">not</span> be seated in the lands.

Case prep is done, and I will shoot with 0,004" clearance in the neck.

As I'm waiting for my rifle I have read alot of article's and made my own load development procedure:

<span style="color: #000099">7WSM load development

Components:
A max 162grs
Hodgdon 4831SC
Federal 210 match LR
Winchester neck turned brass

1: Load one cartridge with Minimum charge weight and increase by 0,5grs up to 2,0grs above maximum charge weight.

2: Seat bullet 0,130” off lands.

3: Shoot with chronograph, measure and inspect while increasing powder charge. Take notes. (Remember barrel brake in procedure)

4: Obtain max powder charge for my rifle. Note charge, temp, etc

5: Load up 22 cartridges for ladder test. Start with clean barrel. 18+4
foulers. Round Robin: 1 shoot per 3minuntes @ long range. Cool down barrel between round robin sequences.
*: 2 sight in/foulers @100m then RR charge 1 to 6. Clean barrel
*: 1 fouler. RR charge 6 to 1. Clean barrel
*: 1 fouler. RR charge 1 to 6.

6: Perform new ladder test with same fire formed cases and 0,1 or 0,2grs differences in powder charges.

7: Plot in the two ladder tests in excel diagram and compare “sweet nodes”. Compare chronograph readings. Obtain best powder charge.

8: Load 24 rounds. 6 rounds per seating depth changes.
6 rounds with 0,130” off lands
6 rounds with 0,090” off lands
6 rounds with 0,050” off lands
6 rounds with 0,010” off lands
Shoot two 3-shoots groups off all. Compare groups and ES/SD

Fine tune seating depth with 0,002” – 0,005” if needed.</span>

Anything I have missed, need to do?

I've tryed both ladder and OCW, very good results with both. Landed on ladder test here because use will be at long ranges...?

 

[sandwarrior]

Re: Load development for extreme accuracy, Need input

I use Win brass. It's weighed and sorted by every 2 gr. Like you, I've neck turned them.

I worked up a load (relatively light) of 62.5 gr. of H1000 and got 2930 fps. I've used 168 and 180 Bergers and JLK's and 175 SMK's. I've used a fair number of 162 A-max's and HPBT's. They are less expensive but also less effective at ranges past 600-800 yds. I always found best accuracy with the bullets .010" into the lands. But, I found decent accuracy as far off with the Bergers as .050" off the lands. Sierra 175's shot better off the lands though. All were good ranging from .75" to 1.5" @ 300 yds.

 

[jbailey]

Re: Load development for extreme accuracy, Need input

How far do you plan on shooting this bad boy? If far - i.e. 1200+yds - you need to focus a lot on muzzle velocity variation, i.e. getting down ES and SD. OCW is all about reducing barrel whip dispersion, which is good and all, but doesn't say much about MV. I would make sure I had a very good chrono, was using it in the same lighting conditions all the time, and get more data on MV.

Good luck! Don't get too hung up and stressed if something just ain't right

 

[Aimsmall55]

Re: Load development for extreme accuracy, Need input

Damn, sounds like u shouldn't be asking anything. You got nailed for finding your load. All you gotta do now is start pulling the damn trigger.

 

[maggitas]

Re: Load development for extreme accuracy, Need input

I agree with Sandwarrior,

If you are looking for extreme accuracy I would sort your brass and bullets out individually. You may even want to start trimming your Meplats.

Johnny

 

[insight3b]

Re: Load development for extreme accuracy, Need input

You can't measure distance to the lands until you get the rifle...so while you wait just load up some ammo with FL sized brass and a start charge of whatever powder you have laying around with whatever primer and the cheapest bullet you can find seated to minimum COL. When your rifle arrives take it and the scrub ammo to the range for intial zero, bbl break-in and fire-forming. When you get home from the range the 1st time is when load development begins. I have 130 rounds of .308 loaded right now for my newest 700. Its loaded with partial sleeves of primers two different powders and two different hunting bullets I don't expect anything except to have formed brass and a nicked crown after the 1st trip.

 

[JBD56]

Re: Load development for extreme accuracy, Need input

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: insight3b</div><div class="ubbcode-body">You can't measure distance to the lands until you get the rifle...so while you wait just load up some ammo with FL sized brass and a start charge of whatever powder you have laying around with whatever primer and the cheapest bullet you can find seated to minimum COL. When your rifle arrives take it and the scrub ammo to the range for intial zero, bbl break-in and fire-forming. When you get home from the range the 1st time is when load development begins. I have 130 rounds of .308 loaded right now for my newest 700. Its loaded with partial sleeves of primers two different powders and two different hunting bullets I don't expect anything except to have formed brass and a nicked crown after the 1st trip. </div></div>
Good advice here.^^^ The brass needs to be fire formed to your chamber before you will be able to be serious about what works and what doesn't. As others have asked, what is LR to you? I have found that initial combinations tried at 100 yards for load development (best groups at that range), did not work as well at 600 plus yards sometimes. This is especially true with VLD's. The ES and SD are really important for shooting LR as mentioned. You won't be able to do that with only one shot for each powder charge. I would use at least 3 shots at each charge weight to get this info. The only other suggestion would be to try different primers. I was a Federal guy for a long time, but have found some of my rifles prefer CCI BR primers (especially SR primers).

You mention following normal barrel break-in procedures...not sure what that means. You will find more competitive shooters using premium barrels that only clean after a range session, and than only clean enough to ensure there is no initial copper fouling. I have a buddy that competes at a high level in a lot of tactical matches that shoots 10 rounds through a new barrel within 30 seconds of each other for the initial break-in. Seems to work for him, but I have a hard time hammering that many, that fast with a new barrel.

 

[MALLARD]

Re: Load development for extreme accuracy, Need input

win brass ? that brass is shitty

get some lapua

do not increase charge weight 2 grains over the max , why would you do that ?

most OCW loads will be several grains under the max charge weight. In my experince

 

[sandwarrior]

Re: Load development for extreme accuracy, Need input

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MALLARD</div><div class="ubbcode-body">win brass ? that brass is shitty

get some lapua

do not increase charge weight 2 grains over the max , why would you do that ?

most OCW loads will be several grains under the max charge weight. In my experince </div></div>

That would be nice...if Lapua made 7mm WSM

 

[leoestby]

Re: Load development for extreme accuracy, Need input

Hi, thanks for all replies

LR for me is max 1200yards, it will be used betweene 500 and 1200yards.

Barrel break in procedure for me is shoot one, clean and see how it looks and stop when copper fouling stops. As this is an custom barrel the reamer "marks" is the reason for barrel break in.

I'll wait for the rifle before loading any cartridges, because I want to fint max COAL first. The reason for loading 2 grains above max is to save time, I will STOP when pressure signs occure.

Win brass is not my first option, but I have used hours trimming and sorting... Next barrel will be with norma brass and necking down from 300WSM

Meplat trimming is not necesarry for A maxes... (Plastic tip)

Need some time to think about fire foming, It has to be done, but I dont think I whant to fire form all my 200 cases... 7WSM eats barrels...First ladder test without fire formed brass, second with fire formed brass... Then I can see the differents in accuracy as well...

 

[Greg Langelius *]

Re: Load development for extreme accuracy, Need input

I was a shoot/clean/shoot/clean advocate for many years.

I have concluded that this policy is fallacious, because after 100 or so rounds no method is going to look any different to the bore scope. Don't be wasting your time and effort.

IMHO, the only truly important part of break-in is the removal of sharp toolmarks left over from the throating process. Further, I do not consider this to be an abrasive process, but rather, an ablative one. I believe it is accomplished by the ablation from the hot, fast combustion gasses and still solid residues of the burning powder kernels blasting through the throat portion of the chamber/barrel.

While I don't favor getting the rifle really hot in normal practice, I do so because it simply accelerates throat wear. In this instance, that's probably the only time we'd actually want something like that to be taking place.

Greg

 

[Casey Simpson]

Re: Load development for extreme accuracy, Need input


1. Not a good reason to use ladder test as opposed to OCW.

2. When seeking OAL, load all rounds maximum length, take them, your other gear, and a press to the range and bump your bullets there to shorter OAL as you wish. A small press works well.

3. You didn't mention sorting cases, but you probably did that in the prep.

 

[sandwarrior]

Re: Load development for extreme accuracy, Need input

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: leoestby</div><div class="ubbcode-body">Hi, thanks for all replies

LR for me is max 1200yards, it will be used betweene 500 and 1200yards.

Barrel break in procedure for me is shoot one, clean and see how it looks and stop when copper fouling stops. As this is an custom barrel the reamer "marks" is the reason for barrel break in.

I'll wait for the rifle before loading any cartridges, because I want to fint max COAL first. The reason for loading 2 grains above max is to save time, I will STOP when pressure signs occure.

Win brass is not my first option, but I have used hours trimming and sorting... Next barrel will be with norma brass and necking down from 300WSM

Meplat trimming is not necesarry for A maxes... (Plastic tip)

Need some time to think about fire foming, It has to be done, but I dont think I whant to fire form all my 200 cases... 7WSM eats barrels...First ladder test without fire formed brass, second with fire formed brass... Then I can see the differents in accuracy as well... </div></div>

How is the Norma .300 WSM for head hardness? I find the other cases of where I've used Norma that it works great if you don't load it hot. I always get a pretty good amount of case setback and consequent case stretch if loading it hotter. Unlike Lapua that take those loads. Any findings yet?

 

[loaders_loft]

Re: Load development for extreme accuracy, Need input

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: leoestby</div><div class="ubbcode-body">




2: Seat bullet 0,130” off lands.

8: Load 24 rounds. 6 rounds per seating depth changes.
6 rounds with 0,130” off lands
6 rounds with 0,090” off lands
6 rounds with 0,050” off lands
6 rounds with 0,010” off lands


Fine tune seating depth with 0,002” – 0,005” if needed.[/color]

</div></div>

sorry for chopping up your post but I wanted to comment on the bullet seating.

I like to start with bullets jammed or closest to the lands, then work back away from the lands (opposite of the method above). Is there a particular reason you plan to work toward the lands?

Also, you "may" want to buy several boxes and sort your bullets. When being ridiculously meticulous (good past-time for stormy days), I like to sort first by bearing surface and then by weight with the most emphasis on bearing surface.

One last question, if you don't mind. Why did you initially choose H-4831sc?