Bullet impact vs. StrelokPro data

danb · Feb 13, 2019

There is probably more than one factor off in my opinion. chrono could be off, scope height off by 3/8, BC could be off too. It all adds up.

Strelok Pro has a trajectory validation feature, you can calculate the velocity given the actual MOA/inches observed. You can also calculate BC. Using it, if the chrono is off 50-75 fps (about 3%) that might explain the discrepancy.

kooJoe · Feb 13, 2019

Gentlemen,
My scope height was off .25". However, when I adjust my program for that variable I am still unable to have program match (within reason) without adjusting zero to 240 yds. My true drop at 600 yards is 11.5 MOA. Inputing the new scope height, using all variables listed in earlier post, program solution is 12.81 MOA for 600.... too high.

If I input 240 yd zero, use 2813 MV, new scope height of 1.75", and then call for 600 solution the program shits out 11.66 MOA which I would normally round down to 11.5 while shooting. when I call for 1000, it calls for 33.90 (which will be 1/2 MOA to low). If I go into the trajectory truing option and put in my actual drop of 34.5 MOA at 1000, the whole program seems to get close to my actual drops in field, albeit it calls for a slower calculated velocity of 2793. This is doable for me in the field.

Again, as soon as the farm lanes dry up from the rain, Ill go out into the field and re-box (confirm my drops) then check in with you guys. At this point Im either extremely negligent and missing something (like being off .5" on scope height) or I need to get comfortable with the fact that I need to manipulate the program to match what the rifle/bullet is doing.

I really appreciate each of you circling back with suggestions. This stuff drives me crazy, but also is one of the things that makes this hobby attractive to me. A challenge.

Side note, for the last five years I was hand loading hornady 155 Amax bullets. These were proven winners on deer at extreme distances. I have not used the ELDs on deer yet, however the groupings from this factory product are unbelievable. From what I can tell they are basically an amax, but with a different coating. Sorry pure ones! I have gotten too lazy to hand load any more. Thanks again.

danb · Feb 13, 2019

rather than solve for your zero, try solving for velocity using Strelok pro target validation feature. See what velocity you get. could simply be your chrono is off.

Mt Airy · Feb 13, 2019

The temperature is a big thing and zeroing weather. You should enter the temp of the day when you are using the app. And of course the BC must be correct.

Broncolou · Feb 13, 2019

Are you sure you didnt confuse "zero offset" with "zero range" ?

When I true my stuff up in Kestrel/strelok/shooter. I use a base Speed/fps and then add as many different speed/FPS values in the temp colums as I can get in there accurately. Then I go shoot and true the info on paper for the given temp. Then I take and mess with MV/BC until I get all the points on the progam & trued version to match close as possible.

All of that is done after checking gun/projectile info is correct

Pinecone · Feb 13, 2019

danb said:
rather than solve for your zero, try solving for velocity using Strelok pro target validation feature. See what velocity you get. could simply be your chrono is off.

This ^^^^^

Park ranger · Feb 17, 2019

How ate you keeping that slow 155 stable at 1000, and giving you 6" groups? Palma shooters push a much nicer 155 to 3000 fps and can barely keep it mach 1.2. You could be the world champ with that gun.....

kooJoe · Feb 18, 2019

Park ranger said:
How ate you keeping that slow 155 stable at 1000, and giving you 6" groups? Palma shooters push a much nicer 155 to 3000 fps and can barely keep it mach 1.2. You could be the world champ with that gun.....

Park Ranger......Not sure whats so special about a 6" group at 1000... The attached is a picture of my rifle's grouping at that distance, but this was with my hand loads which were neck sized only, traveling faster, set close to lands etc. My ex father in law shoots much tighter group at 1000 with his 6.5 creed (i know this is very different). Everyone I shoot with says I should try competitive shooting. Ready to really have your mind blown? I spent less than $2,400 setting this rifle up.

Anyhow, I did have a chance to reboot my rifle with the factory rounds. with horizontal adjustments in 10" increments at 100, the scope tracked perfectly plumb and dialed true minutes. I re-zeroed for 100yds instead of my typical 200 yd zero. Same issue with actual bullet path versed ballistic tables.

To get the bullet path to line up within reason to the program, I had to do what everyone suggested (and what I have always relied on in the past... massaging the input data)... massaged BC up to .495 from .463, increased velocity from 2813 to 2830, and manipulate my zero from 100yds to a 146 yard zero.

Again I really appreciate all of you chiming in on this. Thank you!

PS can't figure out how to get picture to spin so that its upright. Oh well.

Park ranger · Feb 18, 2019

I guess when I think groups, I think 10 to 20 shot groups. Put 17 more in that group you could have your name here:

bergerbullets.com/national-records/nra-records/

kooJoe · Feb 18, 2019

I can remember feeling like a million bucks that day. That sort of shooting always reminds me that 99% of the time it’s never the rifles fault when you miss or shoot crummy groups. Do you have a suggestion for an amateur shooting match for me to try?

Speed3 · Feb 18, 2019

You can try fclass....they shoot out of bridgeville DE. Fclass is either midrange (600 yards) or long range (1k).

You'll shoot 60 rounds for score, 3 relays of 20 and bring some sighters also. I bring 80 rounds and that's more than enough if you know your dope.

X ring is 1/2 moa and 10 ring is 1 moa.

Everyone is always super nice. Bring bipod and rear bag, spotting scope if you have one and a mat.

kooJoe · Feb 18, 2019

Park Ranger.... also, I’m sitting here drinking a glass of rum and looking over that picture I posted. I never paid close attention, but if I zoom in it looks like the impacts are not uniform. Almost like the bullet hit a different way all three times. No?

ToolAA · Feb 18, 2019

kooJoe said:
Park Ranger.... also, I’m sitting here drinking a glass of rum and looking over that picture I posted. I never paid close attention, but if I zoom in it looks like the impacts are not uniform. Almost like the bullet hit a different way all three times. No?

They look pretty typical and for the most part fairly uniform.

Park ranger · Feb 19, 2019

kooJoe said:
I can remember feeling like a million bucks that day. That sort of shooting always reminds me that 99% of the time it’s never the rifles fault when you miss or shoot crummy groups. Do you have a suggestion for an amateur shooting match for me to try?

Pm sent

Bullet impact vs. StrelokPro data

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