Chronograph data

[bdubmkg]

Took out the chronograph today I purchased from a user here and got some data for my 6.5cm and 3006. This is the first time I've used this so I thought I'd ask what others throught of the numbers.
First up, 6.5cm. Hornady brass, hornady 140gr hpbt, and shooters world powder. Bergara premier HMR pro. 24" barrel. Made 10 shots.
Min: 2561 max:2602 avg: 2577. SD 13.7

3006, hornady brass, hornady 155gr amax. 56hr of A4350. Savage action, shelin 24" barrel. Made 19 shots. (One wasn't picked up)
Min: 2757 , max 2848, avg 2809, SD 32.1.

The 3006 only has about 200 rds through it. 6.5 has probably 400 or so.

Good, bad, ugly?

 

[Aftermath]

The 06 could have better SD but.....

Normal





Get it?

 

[rustyinbend]

What really matters is ... Do "you" think you can do better?
Until you get to single-digit SD's ... the answer should probably be "Yes".

 

[spife7980]

What really matters is ... Do "you" think you can do better?
Until you get to single-digit SD's ... the answer should probably be "Yes".

I’d amend that “sd” stuff to “groups” you are satisfied with at the distances you are shooting it. Aka, is it actually doing what you want it to.

I really only use sd to gauge how much I need be willing to fudge my ballistic calculator velocity truing to line up.

 

[straightshooter1]

Took out the chronograph today I purchased from a user here and got some data for my 6.5cm and 3006. This is the first time I've used this so I thought I'd ask what others throught of the numbers.
First up, 6.5cm. Hornady brass, hornady 140gr hpbt, and shooters world powder. Bergara premier HMR pro. 24" barrel. Made 10 shots.
Min: 2561 max:2602 avg: 2577. SD 13.7

3006, hornady brass, hornady 155gr amax. 56hr of A4350. Savage action, shelin 24" barrel. Made 19 shots. (One wasn't picked up)
Min: 2757 , max 2848, avg 2809, SD 32.1.

The 3006 only has about 200 rds through it. 6.5 has probably 400 or so.

Good, bad, ugly?

As spife7980 has pointed out, what's really most important is what you got on paper.

Is the speed you got satisfactory to YOU?

The other data, like the SD's only tell you how well/consistent you're loading your ammo. Low to mid teens is gook, but if you want better consistency, it's take some work (and probably some expense) to get into the single digits. Other than that, the chrono data can be very helpful with ballistic apps to calculate trajectories you might need for any long distance shooting.

 

[supercorndogs]

Do you go to the same range as me? Someone left me some 6.5 creed and 30/06 brass today.

 

[bdubmkg]

Do you go to the same range as me? Someone left me some 6.5 creed and 30/06 brass today.

You in west michigan by any chance? I usually clean up my brass pretty good!

 

[supercorndogs]

You in west michigan by any chance? I usually clean up my brass pretty good!

Na. I was just joking. I figured most in the reloading section collect at least their own brass at the range.

 

[bdubmkg]

As spife7980 has pointed out, what's really most important is what you got on paper.

Is the speed you got satisfactory to YOU?

The other data, like the SD's only tell you how well/consistent you're loading your ammo. Low to mid teens is gook, but if you want better consistency, it's take some work (and probably some expense) to get into the single digits. Other than that, the chrono data can be very helpful with ballistic apps to calculate trajectories you might need for any long distance shooting.

So the speeds are good in my book for what I'm doing. 6 months ago I had access to a 1500 yard range on a regular basis. Now all i can do 300 yards.

That said, are the bigger cased rounds like the 3006 more prone to larger SDs vs smaller like my 6.5? I don't crimp my rounds and all the brass is processed the same for both calibers. That said, the 06 dies are Lee and I've noticed that there is more neck tension in the 06 than 6.5. Not sure if fixing that will help.

 

[spife7980]

So the speeds are good in my book for what I'm doing. 6 months ago I had access to a 1500 yard range on a regular basis. Now all i can do 300 yards.

That said, are the bigger cased rounds like the 3006 more prone to larger SDs vs smaller like my 6.5? I don't crimp my rounds and all the brass is processed the same for both calibers. That said, the 06 dies are Lee and I've noticed that there is more neck tension in the 06 than 6.5. Not sure if fixing that will help.

Generally the longer and skinnier the round the harder it is to maintain consistent ignition. So old style cases generally will have higher sds just due to how much more longitudinal space there is for powder to lay differently in.

What is your interference fit? (“Neck tension” outer neck diameter of sized vs loaded brass, how much does the bullet swage the case neck open?)

 

[straightshooter1]

So the speeds are good in my book for what I'm doing. 6 months ago I had access to a 1500 yard range on a regular basis. Now all i can do 300 yards.

That said, are the bigger cased rounds like the 3006 more prone to larger SDs vs smaller like my 6.5? I don't crimp my rounds and all the brass is processed the same for both calibers. That said, the 06 dies are Lee and I've noticed that there is more neck tension in the 06 than 6.5. Not sure if fixing that will help.

Not only are smaller caliber (like 6mm) easier to get low SD's, they're easier to maintaining "natural point of aim" with its less recoil adding to ability to shoot smaller groups.

 

[parkerg31]

I like to always shoot for single digit SD's as a handloading goal, but understand it is not always realistic. For example on my match rifle (6 Dasher), I will not accept a load that shoots more than single digits and half moa as I need the greatest performance possible. On my 2 gun AR that I only shoot to 500, 1moa and 25SD has won me a few two gun matches. On my hunting rifle I care more about group size than SD as I do not shoot past 200 where I am at (hunting load shoots .4moa at 17SD).

I say all this to make the point of it depends on what your personal goals are and the purpose of the load.

 

[bdubmkg]

What is your interference fit? (“Neck tension” outer neck diameter of sized vs loaded brass, how much does the bullet swage the case neck open?)

this I do not know. I'll have to check next time I'm with my equipment.

 

[bdubmkg]

I say all this to make the point of it depends on what your personal goals are and the purpose of the load.

So other than neck tension and consistent seating depth, would the next thing to keep my eye open for would be checking each case for fill capacity?

 

[Aftermath]

So other than neck tension and consistent seating depth, would the next thing to keep my eye open for would be checking each case for fill capacity?

It's a rabbit hole.
Brass consistency...all the same brand, weight the same, capacity the same, brass hardness the same, sized the same, same clean
Primer...seating the same, ignition the same
Charge....powder humidity controlled, weight the same, same lot #
Projectile...same weight, diameter, base to ogive consistent
Just how far are you willing to go to catch the rabbit?

To your question, neck tension has probably more impact on SD than others. Then condition of the neck (dirty, annealed...). Charge weight. Sizing consistency.

 

[bdubmkg]

Generally the longer and skinnier the round the harder it is to maintain consistent ignition. So old style cases generally will have higher sds just due to how much more longitudinal space there is for powder to lay differently in.

What is your interference fit? (“Neck tension” outer neck diameter of sized vs loaded brass, how much does the bullet swage the case neck open?)

Got the case measurements today. Checked 5 cases and all were the same. Inside .303
Outside. .330. I forgot to get my calipers to measure a completed round, but in theory, shouldn't it just bump open to .335?

 

[spife7980]

Got the case measurements today. Checked 5 cases and all were the same. Inside .303
Outside. .330. I forgot to get my calipers to measure a completed round, but in theory, shouldn't it just bump open to .335?

In theory, yes, but it can be hard to accurately measure inside of rounds.

5 thou of interference fit is a bunch for "match grade" stuff, that much tension is more along the lines of shtf vs precision. But if it shoot how you like then so be it. Changing the neck tension will require to verify/change the load recipe.

 

[bdubmkg]

In theory, yes, but it can be hard to accurately measure inside of rounds.

5 thou of interference fit is a bunch for "match grade" stuff, that much tension is more along the lines of shtf vs precision. But if it shoot how you like then so be it. Changing the neck tension will require to verify/change the load recipe.

So at this point the expander needs to be checked to see if it's undersized I'm assuming. According to Lee, the expander should be 3.07.

 

[straightshooter1]

So at this point the expander needs to be checked to see if it's undersized I'm assuming. According to Lee, the expander should be 3.07.

I've got both Lee's neck sizer die and full length die. Both came with the same size of .307 mandrel and their "expander ball".

The best way to get an accurate ID of a case neck is with pin gauges. If you used a caliper to get measurement, it's really hard to get a good ID measurement, especially if your not using a high quality caliper. And don't forget about springback, which as much as .001 - .002 after 24 hrs. and this can vary depending on the particular brand and/or caliber of brass you're working with. Though a Lee expander is .307", I think it's expected the ID to spring back to something like .306 - .305.

Lee does sell smaller expanders, but usually those are sold separately from their dies.