reducing extreme spread

[The Lawn Ranger]

Reloaders,

I have been reloading for about 2 years now and feel I have a pretty good handle on it.....I have been developing a load for a custom 284 in a long action and seem to be getting good velocity (2980 fps) with outstanding accuracy (1/4 minute at 100 yds.). The thing that has me perplexed is no matter what load I develop (accurate or not) I seem to get an ES between 30-40 fps. I wanted to try to get those numbers down.

My plan is to use shoot with consistency out to 1500 yds. but need to better understand the importance of extreme spread to possibly eliminate one more external variable. Correct me if I am wrong, but is ES reflected in vertical spread
at distance?

I am wondering if the following factors might play a critical role in minimizing ES:

Brass prep:
1. turning necks
2. trimming to length
3. reaming flash holes

*I have very consistent neck tension currently (Redding Comp bushing dies) and use sized up 6.5 x 284 Lapua brass.

I use a RCBS Chargemaster 1500 to measure loads (4831sc)

I should probably try a different chrony as well....

Any advise on this subject would be greatly appreciated.

Thanks,

John

 

[psinclair]

Re: reducing extreme spread

Russian primers improved my ES. I use the Tula Large Rifle Magnum in my .308's, 6XC and .260's. Cheaper too.

 

[MtnCreek]

Re: reducing extreme spread

Hotter primers, powders that give good accuracy at higher pressures and adjustments in bullet jump have made differences in some of my loads.

I would keep the brass trimmed to your spec, but you're probably not seeing much stretching. IMHO, flash hole deburring on Lapua brass is a waste. YMMV.

How accurate is the Charge Master?

 

[MitchAlsup]

Re: reducing extreme spread

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: m14er</div><div class="ubbcode-body"> I seem to get an ES between 30-40 fps.
<snip>
Brass prep:
1. turning necks
2. trimming to length
3. reaming flash holes
</div></div>

30 ES implies about 10 SD which is exemplarary for 10 shot SDs.

In any event, you are down in the real where every little thing starts to "get you".

Turning necks is unlikely to help ES/SD numbers; accuracy yes MVES probably not.
Trimming cases might not help, but at least it won't hurt anything and might benefit.
Reaming flash holes helps my loads in Win brass, but not in Lapua brass.

 

[The Lawn Ranger]

Re: reducing extreme spread

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MtnCreek</div><div class="ubbcode-body">Hotter primers, powders that give good accuracy at higher pressures and adjustments in bullet jump have made differences in some of my loads.

I would keep the brass trimmed to your spec, but you're probably not seeing much stretching. IMHO, flash hole deburring on Lapua brass is a waste. YMMV.

How accurate is the Charge Master?

</div></div>

It is not the most accurate, especially with the larger grain powders like 4831sc.

I generally get a good throw but notice sometimes it can overthrow by .2 grains.

I did notice that RE17 meters better but then there is the whole supposed temp sensitivity thing to deal with in the hotter months.

What do you measure your powder with?

 

[MtnCreek]

Re: reducing extreme spread

I don't know anything about the .284, so I'm totally ignorant there.

Hotter primer may affect accuracy differently, depending on other factors. Mag primer + adjustment in COAL might result it same accuracy and reduced ES.

Depending on what I’m shooting, it either goes straight from measure to case or I set the measure a little light and trickle the last few tenths on a beam. The question about the Chargemaster was as much me wondering how well they work as it was about trying to help.

 

[The Lawn Ranger]

Re: reducing extreme spread

The Chargemaster is a good all around measure and faster to be sure. I have not seen these ES' with any of my other calibers. I would recommend the CM to anyone
as it has served me well.

I might try all that was mentioned here including switching to cheaper primers.

I am going to shoot this load out far over the weekend.

 

[Hookturnr]

Re: reducing extreme spread

Biggest thing to help mine was to keep my cases annealed every other firing(300rum) and trimmed to a consistent length. Makes for very consistent neck tension and is the only thing that showed me a change in deviation that was measurable beyond the error of my chronograph.

 

[shooter.dm]

Re: reducing extreme spread

Try shooting each shot through a cold bore

 

[shoot4fun]

Re: reducing extreme spread

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: m14er</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MtnCreek</div><div class="ubbcode-body">Hotter primers, powders that give good accuracy at higher pressures and adjustments in bullet jump have made differences in some of my loads.

I would keep the brass trimmed to your spec, but you're probably not seeing much stretching. IMHO, flash hole deburring on Lapua brass is a waste. YMMV.

How accurate is the Charge Master?

</div></div>



It is not the most accurate, especially with the larger grain powders like 4831sc.

I generally get a good throw but notice sometimes it can overthrow by .2 grains.

I did notice that RE17 meters better but then there is the whole supposed temp sensitivity thing to deal with in the hotter months.

What do you measure your powder with? </div></div>

Have you done the McDonald's straw mod to your CM? Do a search for it on here. It helps a lot with accurate metering.
This is just my opinion but if I had a load that my rifle liked really well and it had a 40FPS extreme spread I would just shoot the hell out of it and not worry. Even more so if that 40 FPS was consistent across a lot of environmental changes.

 

[427Cobra]

Re: reducing extreme spread

My SD/ES is always below 20, a super accurate scale like my Gen2 Prometheus is the answer to your problem IMHO.

 

[MALLARD]

Re: reducing extreme spread

your not deburring your flasholes already ? you should be.

i wouldnt turn my case necks unless i have less then .005 case neck expansion. ( like , .003 ). I found turning cases for standard chambers only lowers accuracy.

ya trim your cases , you need to if your going to use a flashole tool

ES will effect your vertical but it will effect your horizontal as well because the variations in TOF will change how long your bullets will be effected by the wind. So both.

 

[The Lawn Ranger]

Re: reducing extreme spread

I was under the impression that you did not need to ream flash holes on Lapua brass.

I do uniform pockets but there is minimal need for this on Lapua brass as well as they are extremely uniform from the get go.

I have 3 firings on this brass and will trim to length to see if this helps.

Try the McDonalds straw trek on the CM 1500

The Prometheus is a little out of reach currently-but someday when I get serious about reloading perhaps.....

Also, I will try some different primers and perhaps hand measure 20 rounds for consistency.

Thanks for everyone's advise on this matter.

 

[MtnCreek]

Re: reducing extreme spread

Have you weighed or measured the capacity of your brass? Lapua is good stuff, but it wouldn’t take much difference to result in a +/-20fps.

Good luck.

 

[The Lawn Ranger]

Re: reducing extreme spread

Nope. I will do that as well.

 

[MALLARD]

Re: reducing extreme spread

buy bullet uniforming tools , ogive/bsc , meplat , bullet pointer. weight sort your bullets , your groups will get allot smaller after doing all that stuff.

 

[The Lawn Ranger]

Re: reducing extreme spread

Did the McDonalds straw thing and the throws have already gotten more consistent. Thanks