Varminterror
Member
- Joined
- Jul 17, 2016
- Messages
- 14,947
Yes, I’m pointing out the fact short range groups are not as dependent upon velocity as are long range groups.
1) Don’t get too down on your loads just because your small groups don’t coincide with consistent velocity.
2) You might not need to chase velocity consistency at all for 100/200/300 yard league play. I would not be surprised if some of the winners of their matches or even league seasons have done so with 40-80fps ES loads. I’d be more surprised if NONE of their winners didn’t have 40-80fps ES loads.
3) Considerably better bullets can be bought for far less than 80¢ per bullet. I have shot tens of thousands of 77 SMK’s for many years, and now around 10k 73 ELD’s in the last ~4yrs, and I pay 25-30¢ for the 73’s, and ~40¢ for the 77’s (a lot more than they used to be). I don’t even pay 80¢ for the Berger 6mm bullets I use for PRS competition - hell, I don’t even pay 80¢ each for Hornady 110 A-Tips... Practicing with cheap pills is fine - I shoot boatload of 50grn Vmax’s for that purpose in 223/5.56, and I shoot 22LR and 223/5.56 in practice instead of 6 Dasher or Creedmoor to save component cost. But when you’re pushing the limits and trying to shrink groups, it’s pretty easy to “buy accuracy” by using a more fitting bullet instead of FMJ’s. If you’re getting slightly sub-MOA with FMJ’s, I’d expect your process to be able to produce 1/2-3/4 MOA with little effort just by changing bullets and using the same steps to work up the load.
As an example of the disconnect between short range group size and velocity - or rather several examples within one test set... This is a 100yrd chronograph test I use to determine velocity node for long range competition, but since I need to shoot at SOMETHING, not just cross the chrony, I shoot each load at individual points of aim, just because... if we read between the lines a bit here and analyze these groups against their velocity, you can see how little velocity stability has on 100yrd group size.
• The middle target on the bottom is 42.2grn, 3 shots in ~1/4moa, but there’s 28fps spread among the fastest and slowest in that group.
• The smallest group on the page is the left most on the bottom row, which is effectively an anti-node for velocity stability, and has 15fps spread within the group.
AND MOST RELEVANT:
• If we superimpose ALL of these shots onto one point of aim as if I had shot them all at the same target would yield a group between .5-6”, which isn’t great, but not bad - BUT - it reflects 120fps (exactly) between the fastest and the slowest shot in this entire experiment.
This process is designed to find stable velocity nodes for long range shooting, so I ALMOST disregard the group sizes on target. In this instance, conveniently and coincidentally two of the smallest groups on the page do coincide with my node, but you can see the other two nodes at either end do NOT align with the smallest groups. If I shot that same test again, the group sizes can easily swap ranking, as there’s really no statistical validity to the comparison of group size on this page.
41.0-42.4 grn H4350 in 0.2grn increments, L to R top to bottom, 100yrds, Berger 105H, Hornady Brass I wanna say with 4-5 firings and no annealing, 6 Creed, BR2 primers, ~200 rounds on the barrel since the last cleaning. Table and curve reflect the velocity profile of each of 3 series’, with average, SD, and spread/ES displayed.
Again - 120fps spread here yields a ~1/2MOA group at 100yrds (despite 1.4grn powder variance). It won’t look like that at 1000, but you wouldn’t be shooting 1000yrds in your 100/200/300yrd league, so the same work doesn’t need to be done in the same way.
In your shoes: I’d find a bunch of 69 or 77 SMK’s or 73 ELD’s, or even 50/53/55 Vmax’s and work up a load, and don’t distract yourself with the chronograph until you’re shooting far enough that it’s not just a distraction.
