Vertical Dispersion: Can this be addressed with seating depth?

[OzzyO20]

So I found a node that brings my 1,000 dope up to a .5 MIL less drop with out any pressure. Only thing is the rounds were strung vertically. Can seating depth be adjusted to negate this or do I need to move on? It was under 1/2 MOA, but I only shot it at 100, so I'm unsure how bad it would open up downrange.

 

[Deleted member 113831]

Vertical can be caused by a number of things. If your vertical happened to be caused by the bullet exiting the barrel in the middle of it's nodal travel, then yes. If caused by shooter position, varying neck tension, poor load consistency etc... then probably not.

You have to determine your root cause before appying a solution.

 

[OzzyO20]

I'll reload that particular charge and run more than 5 rounds. I will say I anneal after every firing and my 'go to' load had an ES of 10 and SD of 3.6 that day, and was doing wonderfully accuracy wise. I'm also not a human ransom rest, but learning this gives me a reason to revisit it. Thanks @Skookum

 

[KWilson]

What calibre? What bullet? What powder? What type of shooting?

 

[OzzyO20]

What calibre? What bullet? What powder? What type of shooting?

Seems that if seating depth can be used to adjust vertical dispersion, none of this is relevant (I could be totally wrong). But 6.5 CM, 130 Berger Hybrid AR, H4350, and I shoot PRS but this was off a bidpod and bag on my belly in the prone.

 

[OzzyO20]

Currently I'm .020" off the lands. Would I go closer to the lands to start testing?

 

[Deleted member 113831]

Currently I'm .020" off the lands. Would I go closer to the lands to start testing?

Personally, I would go deeper. I don't like being any closer than .020"... others would disagree.

 

[OzzyO20]

Personally, I would go deeper. I don't like being any closer than .020"... others would disagree.

Any dangers of pressure creeping up? At .020" I'm very near 100% capacity. Not crunching powder, but the 'rattle' is as faint as it gets.

 

[Deleted member 113831]

Any dangers of pressure creeping up? At .020" I'm very near 100% capacity. Not crunching powder, but the 'rattle' is as faint as it gets.

That is kind of a case by case situation. It depends on the particulars of the bullet and throat. The idea is to have enough running room for the bullet to smoothly engrave into the lands upon firing. If you get too close then things can get spikey.

Benchresters will touch or jam bullets but they are an extremely specialized situation, and even thier loads can be finicky and may sometimes need tuning for current ambient temps.

If this is a gas gun, I wouldn't go any closer to the lands.

 

[KWilson]

Seems that if seating depth can be used to adjust vertical dispersion, none of this is relevant (I could be totally wrong). But 6.5 CM, 130 Berger Hybrid AR, H4350, and I shoot PRS but this was off a bidpod and bag on my belly in the prone.

Its relevant as it depends on your shooting technique, how accurate your reloading is, and what the conditions are like on the day...things like a headwind or tailwind could affect vertical if by chance you're getting caught out on pick-ups/drop-offs for example...likewise your breathing. Try and eliminate the shooting variables one by one to make sure you're confident it's the load/seating depth and not something to do with your technique. Have you got any ES/SD data on the load you're running? I'd start the Hybrids at a 5 thou jump, then move to 15 thou jump, 30 thou jump, 45 thou jump and 60 thou jump as far as seating depth is concerned. One of those 5 jumps should prove tighter than the others, then you fine tune either side to verify. Provided your reloading technique/load data is accurate as possible, it's where I would start anyway.

 

[Deleted member 10043]

Something on the rifle is moving if it is consistent and that includes you. Consistent .5 moa groups is not your ammo. Why does every answer to every problem is ammo problems at 100 yards. Might as well say you have an over priced POS if you have to waste your time and expendable assets finding the magic nodal frequency, lol. You can tune a piano but you can't tuna fish. Based on the little information provided you have either a slight problem with the rifle or it is just a slight problem with the fundamentals. Your ES tells me to stop and think with your head.

 

[Milo 2.5]

Maybe some pics of your groups may help. More detailed info on your load too. If your target shows bullets stacked vertical in a pattern at 100 yards, it's probably your powder charge causing it. If your vertical is satellites from 2 shots, it could be pressure.
Do you have any means of seating bullets long and taking your press, die, caliper to the range and find the seat depth?

 

[OzzyO20]

Something on the rifle is moving if it is consistent and that includes you. Consistent .5 moa groups is not your ammo. Why does every answer to every problem is ammo problems at 100 yards. Might as well say you have an over priced POS if you have to waste your time and expendable assets finding the magic nodal frequency, lol. You can tune a piano but you can't tuna fish. Based on the little information provided you have either a slight problem with the rifle or it is just a slight problem with the fundamentals. Your ES tells me to stop and think with your head.

View attachment 6964174

I shot the charge in the first comment once. That day I shot multiple 1/4 MOA groups with a known load, the one I have the numbers on. The rifles is an AI, and I took 2nd at a PRS match 3 days later with it. So piss off with you’re fundamentals speech. I want to know if seating depth can negate vertical stringing, not your opinion.

Also, an ES of 10 is bad huh? First time I’ve heard that stated.

 

[OzzyO20]

I'll load 15 up at that charge weight and re shoot it. It was really one group and of all the different loads I tried that day, it was the fastest and most accurate other than what I normally run. It was textbook vertical stringing though. all touching up and down (no other charge weights produced that pattern all day, or ever). I should of just asked if seating depth is a means of getting rid of vertical dispersion.

As for taking things to the range, I do have my press on a In-line Fabrication mount..... Just not sure I wanna go through all that.

 

[Milo 2.5]

I'll load 15 up at that charge weight and re shoot it. It was really one group and of all the different loads I tried that day, it was the fastest and most accurate other than what I normally run. It was textbook vertical stringing though. all touching up and down (no other charge weights produced that pattern all day, or ever). I should of just asked if seating depth is a means of getting rid of vertical dispersion.

As for taking things to the range, I do have my press on a In-line Fabrication mount..... Just not sure I wanna go through all that.

If you are going to shoot 15, can you shoot at distance, it's a way better barometer than at 100?

 

[OzzyO20]

If you are going to shoot 15, can you shoot at distance, it's a way better barometer than at 100?

I have 250 yards about 15 minutes from home. I'll move it over there and see if strings. If you don't think 15 is adequate I can do more? Just seems like 3 five round strings would tell me if it is in fact stringing. From there I'll start a depth test.

 

[Milo 2.5]

I have 250 yards about 15 minutes from home. I'll move it over there and see if strings. If you don't think 15 is adequate I can do more? Just seems like 3 five round strings would tell me if it is in fact stringing. From there I'll start a depth test.

No use loading ammo if you do not like it's performance, you'll be fine.

 

[spife7980]

I would skip the multiple groups of the same thing and just do a depth test, five at what you found, five .010 shorter and five at .010 longer. Maybe extend test that another step or two shorter if you have the time. Only way to know is to test so why beat around the bush?

 

[Deleted member 10043]

I never said your ES was bad moron and as an accomplished fucking shooter why are you asking incredibly stupid questions. You placed in a match. That doesn't mean your not a "bad good" shooter. Keep fucking with that seating depth. And having an AI is no reason to overlook the obvious, snowflake. And this goes for all you other unicorn chasers motherfucking up the sport with stupid ass solutions and have nothing to do with you being the problem or the fact your shit isn't wired tight. Just .003" more inches and you're Annie Oakley. Nice dress.

 

[NineHotel]

Seating depth can effect overall dispersion, yes - that is how I tune a 2156 Sierra. Typically I chase vertical by tuning to ES. True vertical dispersion at extended ranges is dependent on velocity. Group size and shape can vary from many things, but ES needs to be 20 FPS or less to hold a half minute of elevation at 1000 yards. Any more than that and you are chasing POI with the elevation knob. Given that high and low velocity rounds occur at random, you don't know if you are correcting off a slow or fast round, and what the next round fired will be. Chase elevation with ES and group size with seating depth is what I'd recommend.

 

[KWilson]

Just on the seating depth, my gunsmith runs a 7SAUM and typically likes to run 180gr Berger VLDs - jammed. He normally starts with a 10 thou jam and quite often doesn't have to change much after that - they typically shoot very well. He recently altered his seating depth in the early stages of tuning and jammed them 14 thou as opposed to 10. The difference it made to his vertical dispersion was very noticeable with an immediate improvement at distance. Your 250 yard range should definitely tell you a lot more if you load up a batch of 25-30 rounds and run your depth test.

 

[brushbuster49]

I was testing loads for a new rifle yesterday. I only had one group that strung vertically so am I too assume it was user error? Even though it did string vertically it was the tightest group I shot. Comments?

 

[memilanuk]

Comments?

Start your own thread?

 

[PAYDIRT]

Maybe I don't know what I'm doing but load testing at 100 has at times been useless for me. I have a 233 load at 23.5 that shoots good 100-800. I was sick and not working one time so I thought "I'll make it better" so I stated playing and had a load @ 23.9 that was a little longer. Shot 2 5 round groups at 100 and it was a laser. So another couple days of cabin fever while being sick I loaded a bunch of my "new/better" load, I was floored by how terrible it was at 350 and beyond. I just don't think 100 is enough to know everything about a load.

 

[brushbuster49]

Start your own thread?

So sorry to offend you. I thought this thread was about vertical stringing.

 

[memilanuk]

It is... and it ran its course.

To get the best answers for your situation, it usually is best to start a separate thread with the details pertinent to your case, rather than risk confusing things.