ES

Well wouldn't call myself greatly experienced reloader but I've rolled a few of my own here n there for the various rifles I've owned
Only factory ammo I've bought for years is the occasional bulk pack for the brass.
No long range sniping but they go ok
Have been playing more recently with a labradar and some load development
Interesting to me that what i consider to be pretty consistent process.including amp annealing,
beam and electronic scales,still produces inconsistant speed and E.S
Some loads better than others but some 40fps over 3 shot groups
Yea,shoots ok and could just go hunting,but you know?
Interested in thoughts on getting better consistency

What caliber?
Jump or jam?
Are you using a vld seating stem/micro meter?
How are you measuring you BTO?
Brass quality and good prep helps alot.
Neck tension- do you clean the inside with copper brush

I don't use any flash gear bit pay attention to the above.
Some calibers are easier than others and it only matters if shooting way out. More important to make sure you are shooting spot on at 300 yards.

I'm sure others will add

Small question with a large answer

Google…….

Internal ballistics
External ballistics

And terminal ballistics

And have a good read of all the headings that comprise internal ballistics

From primer through to muzzle it’s a complex list that in its entirety affects the muzzles release of the projectile, and from there you enter the subject of external ballistics

Fortunately with the ammunition itself we can modify component choices and settings until they work with the rest of the rifle to produce what we want, (consistent and repeatable near identical velocity and barrel harmonics until projectile release)

It’s no one component, it’s the sum total of everything

ES isn't that useful. It only shows your best and worst shot. SD is better for prediction as it shows how your velocity is spread. The down side is you will need more shots to get a valid SD.

For example you could have 10 shots with 5 at 2710 and another 5 at 2750. Or 1 shot at 2710, 8 at 2730, and one at 2750. Both have the same ES and average, but one is signifficantly better. These cases aren't likely to occur because velocity is normally distributed, but it illustrates the difference.

7RM,unsure of jump as used OAL of load data but probably 0.150"
no vld stem or micro
dial vernier, hornady comparator
norma brass,whats good prep?
neck sized,check length,chamfer,clean inside of neck?
check

Powder charge & type of powder can play a big part in ES. With some powders i have found when getting close to a max charge, ES can start getting quite big & by dropping the charge weight back a bit & sacrificing some velocity, the ES/SD can come down. Not always the case and doesnt always happen at max or close to, but have found that with some powders. If you have been finding your best groups based on charge weight & coming back down in powder charge gives you better ES/SD but worse groups, you can then do a seating depth test to tighten the groups back up.

Brass prep also plays a big part too as mentioned above, especially if its poor quality brass. If you have brass that has a big variance in h20 capacity, this will effect the velocity quite alot with the exact same powder charge. I mainly use lapua brass where i can & its pretty consistent but have used norma brass in one of my old rifles once and ended up having to sort it into 3 different batches as there was quite a difference in weight/capacity across the lot of 60 odd cases that i had.

As you initially said good to go hunting. I just ran a 40 fps difference through strelok for my 3006 and got a 2 inch change in poi at 500 yds. I wobble far more than that.

Greetings @Lurch,
Welcome to the giant rabbit warren of handloading. Consistency is the key. Keep your cases in batches and load them all together at one time. This keeps the loading history the same. As far as case prep goes less is best. A neck chamfer inside and out plus running the expander button in and out of the case neck is all that is generally needed. Do not FL size. Buy decent quality new cases. No amount of fiddling is going to make an average case into a good one. Resizing of belted cases is tricky and can take some specialised kit to remove a bulge in front of the belt if you are sizing to just bump the shoulder back a minimal amount. FL sizing with the die down hard on the shell holder can result in very short case life. Rather than worry about SD I would suggest some accuracy testing at the maximum ranges that you are likely to be shooting. Hard data is worth more than a pot full of opinions.
Regard Grandpamac.

Yea ,I can see brass capacity having a decent affect on velocity.
I've always used norma brass thinking it to be better than most,maybe not so much after reading stuff here?
Yea,playing with oal is next I think.

Quote:

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Originally Posted by Lurch

Yea ,I can see brass capacity having a decent affect on velocity.
I've always used norma brass thinking it to be better than most,maybe not so much after reading stuff here?
Yea,playing with oal is next I think.

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Norma brass can be softer than lapua but if not stoking it up no problems.

As far as sizing brass goes it's really about not over sizing but still full length.
The majority of top shooters full length but use the redding comp shell holders that make every case perfectly bumped back to avoid tight chambering and also case separation issues.
For me I believe annealing with the amp does make a difference with consistent neck tension.
As has been said before, it's a rabbit hole and its deep!

Sent from my SM-A226B using Tapatalk

Quote:

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Originally Posted by Lurch

7RM,unsure of jump as used OAL of load data but probably 0.150"
no vld stem or micro
dial vernier, hornady comparator
norma brass,whats good prep?
neck sized,check length,chamfer,clean inside of neck?
check

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I use my BTO -Base To Ogive measurement as a rule for measuring as it's far more accurate and ballistic tips can be inconsistent lengths

A vld stem in your seating die allows for the more modern projectile shapes with longer olives and will five you more consistant seating. You can check this by measuring BTO

A micro meter on your seating die will help you you tune jump provided you have measured your maximum length to the commencement of rifling

I use a drill with shell holder to spin my case and insert a copper wire brush into the neck. This helps with even neck tension on the pill.

I have never had amazing results loading for a 7RM and remember chasing my tail with reloading for one.

It is a rabbit i have been down but these days I am more concerned about group size at 100 yards, fine tuning my zero to hit exactly where I am aiming at 300 yards. Then reading environmental conditions so I can decide on weather to take longer shots or not.

Good luck

Yea I measure oal to conform with load data then measure bto and use that measurement to check as I go.

What's a vld seating stem?
Is it just deeper hole inside to allow for longer pointed projectiles?

Quote:

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Originally Posted by Lurch

What's a vld seating stem?
Is it just deeper hole inside to allow for longer pointed projectiles?

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More tapered. Will help with concentricity too

My thought would be 1. Does it have a lot of vertical dispersion at long range? (Afterall that's what really matters) 2. If you are using an optical Chrono, velocities can vary a tonne - even within one session - if the light conditions change.