Chronograph data

[Axis II]

First time using a Chronograph today. What I found odd was some of the rounds had very low velocity compared to others and a load that shoots well had high SD which from what I’ve read is bad. I tried letting the barrel cool completely between shots but the club was doing a match so it was a mad dash to hurry up before they started. What can I do to get the numbers more consistent?

 

[tightgroup tiger]

Where you in the bright sun when you took these readings and how far away was the chrony from you?

 

[Axis II]

Where you in the bright sun when you took these readings and how far away was the chrony from you?

It was sunny for awhile so I put the shades on. Once the clouds came in and the trees shadowed the chrono I took the shades off. I’d say 9-10ft I tried for further away but it was unstable.

 

[WrongHanded]

I'm a little confused by the descriptions. Are all these loads with the same bullet?

 

[Axis II]

I'm a little confused by the descriptions. Are all these loads with the same bullet?

No the pictures have the info.

SMK- Sierra match king with 25 & 25.3gr Varget.

55gr Nosler Ballistic tip with 25.3gr Benchmark

50gr V max with 26.6gr varget

55gr V max 26.6gr.

 

[JFrank]

I never take the shades off

 

[Axis II]

I never take the shades off

I was just going off the directions for the first use. I’ll try it again with leaving them on.

 

[WrongHanded]

No the pictures have the info.

All I see for info is "55 v max Varg 400", "50v max 26.6 Varg 400", "SMK 25 Varg 400", "55 nbt BM 450", "SMK Varg 400 25.3".

So, they're not the same bullet?

Edit: Okay, I see what you added to that post.

 

[WrongHanded]

So if you're using different bullets, which you are, you may find that even though one load with one bullet has a higher SD for the 5 shots, the bullet is a better choice for your barrel. If so, work with that bullet more until you find the best load.

 

[Axis II]

So if you're using different bullets, which you are, you may find that even though one load with one bullet has a higher SD for the 5 shots, the bullet is a better choice for your barrel. If so, work with that bullet more until you find the best load.

So the Sierra and Nosler had the lowest number. Are they not acceptable numbers?

 

[WrongHanded]

So, the match kings are for match shooting I want to do. The Nosler and V max are used for punching paper and varmint hunting. I take it just run with what shoots better? I mainly Chronographed to use a ballistic calculator to get close enough shooting longer ranges. I figure use up the 50 or so of the v max that I have because the gun likes the Nosler a lot better

If you're happy with the loads you have, then don't worry about the SD and just keep shooting them. If you're searching for the most accurate load you can get, and you have one with a certain bullet but higher SD that shoots best already, consider experimenting with that load. I'm far from anything resembling an expert when it comes to reloading, but that's what seems most pragmatic to me.

 

[LaneP]

In my experience, SD's tighten as you achieve the maximum burn efficiency of the powder/bullet/bbl length (etc) combo being used. Some of my favorite loads have not given me stellar SD's.

 

[Axis II]

So, tried some different loads the other night and again, had a load that shot really good at 100yards but velocity, ES, and SD were all high or all over the place.

50gr V max, H322, CCI 450.
AV: 3296
ES: 80FPS
SD: 32FPS
#1-3301FPS
#2--3254FPS
#3--3226FPS
#4---3334FPS
#5--3266FPS

50gr V max, H322, CCI 400.
AV: 3241
ES: 107
SD: 38
#1--3272
#2--3283
#3--3176
#4--3218
#5--3229
#6--3271

 

[JFrank]

So, tried some different loads the other night and again, had a load that shot really good at 100yards but velocity, ES, and SD were all high or all over the place.

50gr V max, H322, CCI 450.
AV: 3296
ES: 80FPS
SD: 32FPS
#1-3301FPS
#2--3254FPS
#3--3226FPS
#4---3334FPS
#5--3266FPS

50gr V max, H322, CCI 400.
AV: 3241
ES: 107
SD: 38
#1--3272
#2--3283
#3--3176
#4--3218
#5--3229
#6--3271

Are you weighing these charges ? If so then to what resolve ?

 

[Varminterror]

I forget where you are in this load development, but remind me how we got to this point that you only used these particular loads for these powders with each bullet?

SMK- Sierra match king with 25 & 25.3gr Varget.

55gr Nosler Ballistic tip with 25.3gr Benchmark

50gr V max with 26.6gr varget

55gr V max 26.6gr.

 

[Axis II]

Are you weighing these charges ? If so then to what resolve ?

Trickled every charge.

 

[Axis II]

I forget where you are in this load development, but remind me how we got to this point that you only used these particular loads for these powders with each bullet?

My Sierra load is done. Now I’m trying to find a decent varmint and cheap steel banger load. The benchmark load has been a proven load for years. The others I ladder loader before the Chronograph until I got good accuracy.

 

[Varminterror]

My Sierra load is done. Now I’m trying to find a decent varmint and cheap steel banger load. The benchmark load has been a proven load for years. The others I ladder loader before the Chronograph until I got good accuracy.

What MAY be happening: you chased rabbits and now you realize you didn’t catch a squirrel too. You did load development based on group size and POI, and now the new tool is moving the goal post, to apply a new standard which wasn’t previously targeted. Which is fine - if the loads shoot small for what you need at short range, they’re probably fine even with big velocity variability.

I’m not terribly convinced a guy needs to be inside a compensation node to shoot small at short range. In principle, being in a compensation node should help shrink velocity variability, but it won’t solve everything. So you might have great, small shooting short range loads, which are all over the map for speed - and that’s ok.

If these loads need to reach farther, then you might need to run a ladder across your chrony and see where harmonics along to produce small groups AND stable velocities.

 

[lordpaxman]

So, tried some different loads the other night and again, had a load that shot really good at 100yards but velocity, ES, and SD were all high or all over the place.

This is one of the what-the-heck moments when you first use a chrono. You expect your pet load to have an SD of 1. Or you run a set of test loads, pick the lowest SD and expect that to group the best. Either may happen, but never for my loads. You’re going to realize you are measuring your process, combination of components, gun, and shooting consistency, and there are lots of variables there. I use a chrono, they’re a useful tool, the one thing I would suggest is running a known load across it to check function. I use either Blazer 9mm or CCI SV, run them first and see that things are working. Good luck.

 

[JFrank]

Trickled every charge.

I never tune by a chronograph but ‘Wow’ 107 fps es is definitely a sign that something is off. You report good grouping at 100 yards, perhaps stretch out to 200 or 300 yards and confirm small and repeatable groups impacting the same poa.

 

[Axis II]

I never tune by a chronograph but ‘Wow’ 107 fps es is definitely a sign that something is off. You report good grouping at 100 yards, perhaps stretch out to 200 or 300 yards and confirm small and repeatable groups impacting the same poa.

I know it’s only 3rds but this is the load I shot over the chrono. Tried it with 5 and 7-8 shots the day I did the chrono testing and it shot the same. I more needed it to help with a ballistic calculator and turret markings.

 

[Skgreen]

‘Wow’ 107 fps es

I've got that beat!

Below are 5 shots @ 100 yds. 1 inch targets.
223 using "used and abused" mixed year LC brass

SD 49
ES 131
TAC / RMR 69 gr.



SD 69
ES 178
22.4 TAC / 53 gr. HPFB Match 2626 fps average. (Starting load)



Lotsa things come into play when shooting. The closer you are to your target, the less important some of those things become.

 

[JFrank]

I know it’s only 3rds but this is the load I shot over the chrono. Tried it with 5 and 7-8 shots the day I did the chrono testing and it shot the same. I more needed it to help with a ballistic calculator and turret markings.

Assuming a drop chart ? I got ya’ I really need to do that for a couple rifles myself, thanks for the reminder.
Question; with a hundred or more feet per second spread doesn’t that make it tough to get the correct firing solution ?

 

[Axis II]

Assuming a drop chart ? I got ya’ I really need to do that for a couple rifles myself, thanks for the reminder.
Question; with a hundred or more feet per second spread doesn’t that make it tough to get the correct firing solution ?

I would assume it would so j want to get the numbers better.