dihardhunter
Lil-Rokslider
- Joined
- Dec 5, 2012
- Messages
- 177
Debated on whether this was more appropriate for the Firearms or Long Range subforum, went with this one only because I figured more guys are using drop chart apps and such...any help is appreciated.
Broke in a 6.5 Creedmoor, limited issue Browning X-bolt Stalker 26" barrel past couple weekends w/ 140 gr. match grade. This weekend transitioned to 143 eld-x for past 20 rounds or so of dialing in my zero and putting the chronograph to use. Zeroed at 100 yards, easily sub 0.5 MOA - cutting same bullet holes with nearly every round at that range with the eld-x's. Advertised BC is 0.625. I took average of 3 chronograph shots and getting 75 FPS more than box advertises at 2,775 FPS. At this stage, the gun is shooting BETTER than I had hoped.
(Scope I'm working with is SWFA 3-15x in MRADs if that matters to anyone, checked tracking and everything seems perfectly responsive.)
Anyways, punched all that info into Strelok and walked out to 2, then 300 yards. Groups expanded a little, still sub-MOA...chalk that up to operator error - never claimed to be a dead eye, BUT the more concerning thing was that my bullets were consistently falling further and further below the bull. Needed another click at least at 200 yards and 2+ extra clicks to make dead nuts at 300 yards. Obviously the discrepancy is going to exaggerate the further out I go. Again working in MRADs. Worked backwards at the end of the session to drop 1 round in at 100 yards, and punched the dead center of the bull - so it's not a bumped zero I'm dealing with.
Put this chart together to show what Strelok says should be happening with drop trajectory according to my input, then played with numbers to adjust FPS all the way down to 2575 (which is 200 FPS lower than what my rifle is actually spitting out rounds) to do my best at replicating the drop I was observing in the field. Hated to do that but wasn't sure what else to do. By experimenting, it seemed the FPS factor was the easiest to adjust and see a measurable response in the app output, as opposed to tweaking the BC or scope height, etc. Not sure how this new (faked to mimic reality) output will hold up at 400 or 500 yards and beyond, but the difference between what my load should be doing and what I'm seeing off the bench are the difference of an entire kill zone at 500 yards - nearly 10". Blue is Strelok's (and a couple other apps I cross-checked) and orange is the reality I'm experiencing.
I've triple checked my input data from scope height to FPS to BC to anything I can think of, but this is sort of new territory for me. Any advice or guidance from those more experienced. Thanks in advance.
Broke in a 6.5 Creedmoor, limited issue Browning X-bolt Stalker 26" barrel past couple weekends w/ 140 gr. match grade. This weekend transitioned to 143 eld-x for past 20 rounds or so of dialing in my zero and putting the chronograph to use. Zeroed at 100 yards, easily sub 0.5 MOA - cutting same bullet holes with nearly every round at that range with the eld-x's. Advertised BC is 0.625. I took average of 3 chronograph shots and getting 75 FPS more than box advertises at 2,775 FPS. At this stage, the gun is shooting BETTER than I had hoped.
(Scope I'm working with is SWFA 3-15x in MRADs if that matters to anyone, checked tracking and everything seems perfectly responsive.)
Anyways, punched all that info into Strelok and walked out to 2, then 300 yards. Groups expanded a little, still sub-MOA...chalk that up to operator error - never claimed to be a dead eye, BUT the more concerning thing was that my bullets were consistently falling further and further below the bull. Needed another click at least at 200 yards and 2+ extra clicks to make dead nuts at 300 yards. Obviously the discrepancy is going to exaggerate the further out I go. Again working in MRADs. Worked backwards at the end of the session to drop 1 round in at 100 yards, and punched the dead center of the bull - so it's not a bumped zero I'm dealing with.
Put this chart together to show what Strelok says should be happening with drop trajectory according to my input, then played with numbers to adjust FPS all the way down to 2575 (which is 200 FPS lower than what my rifle is actually spitting out rounds) to do my best at replicating the drop I was observing in the field. Hated to do that but wasn't sure what else to do. By experimenting, it seemed the FPS factor was the easiest to adjust and see a measurable response in the app output, as opposed to tweaking the BC or scope height, etc. Not sure how this new (faked to mimic reality) output will hold up at 400 or 500 yards and beyond, but the difference between what my load should be doing and what I'm seeing off the bench are the difference of an entire kill zone at 500 yards - nearly 10". Blue is Strelok's (and a couple other apps I cross-checked) and orange is the reality I'm experiencing.
I've triple checked my input data from scope height to FPS to BC to anything I can think of, but this is sort of new territory for me. Any advice or guidance from those more experienced. Thanks in advance.