The follow up video came out today. Here are the highlights.
I am not a court reporter, so some of my words may be slightly different than theirs, sorry but ya get what ya paid for....
0:00 Intro, a follow up to the previous podcast video
4:00 A 500 shot group didn’t significantly change past 50 shots
6:00 Discussed the procedure used for the rail gun in their lab.
7:00 Barrel heat and cadence
- Cadence was discussed for difference between cooling off versus long strings.
- 30 – 50 shots was too much even for the 1.25” Dia Test barrel profile of the rail gun
- Their test barrels are typically SS single point cut rifling, not button rifles which may have issues with heat
11:00 Was the last video a conspiracy to sell more bullets, ha ha ha, lol.
14:00 Pick a load and go, versus waste time and resources on false load development
14:40 They reiterated the stats problem with small samples
17:30 Why do we shoot groups at all?
21:13 Do what you want to, but own it. We ain’t telling you to follow us if you don’t want to.
22:15 Better to do bad at a local match, than to drive far away and do bad with remorse the whole way home.
24:00 Small samples sizes costs more in reality when it wastes components and work.
25:30 Context is custom versus factory. Properly selected and assembled custom gear shoots better than a factory gun, and expectations are different.
27:20 Because good guns shoot well, expect very little difference in results when using good components.
28:00 Biggest influence on load development in this context – bullets and powders.
29:00 What do you do if you are stocked up on a given bullet and powder and are not happy? Reduce Charge.
31:00 Discussed priority between speed and high BC versus dispersion. Better to accept a good dispersion from a slower, lower BC bullet, than to push for a poor group with speed or trajectory. Dropping charge weight is okay.
31:45 Discussed hypotheses of why dropping charge weights may be better
33:25 Pick a known good powder, pick a known good bullet, reduce charge if you are not happy at first.
33:35 Miles reiterated his observations that seating depth doesn’t show strong effects in their testing.
34:45 Discussion of what jump may be doing. Bullets starting into rifling straight may be a key to getting good performance and small groups.
36:15 Handguns are much more sensitive to seating depth and case volume than rifles with respect to pressure.
37:26 Their tests do not show seating depth sensitivity and that may be because their designs are not “aggressive” meaning they don’t have a short bearing surface that might make them jump sensitive and they don’t use sloppy chamber/neck designs.
38:00 They decide to go back through load development methods for match and for hunting rigs.
38:40 Miles repeats his previous approach on match rifles, discussing based on his 6 ARC and 6.5 CM
- He is invested in Varget and Leverevolution powders as his go to for match shooting.
- His start point is based on the background of several previous barrels and has several spun up and ready.
- He knows to search near 27.5 – 28 grains of Varget with 110 ATip with 30 – 40 jump
- He tests a 20 shot group
- If not happy he checks 0.5 grains to 1.0 grains, and if still unhappy he changes powders.
- If still not happy, he changes to 108, 109, or even 103.
40:38 Miles – if in unknown territory?
- Research and study the most popular powders from competition
- Shoots 10 shot “feeler groups”
- Abandons them if he doesn’t see better than 1 MOA
- Sets personal criteria of 0.75 MOA or better for 20 shots.
42:08 Miles reiterated that across the charge range from book MIN to book MAX, he doesn’t see SD change significantly. He accepts an SD of 13 – 14 at most, prefers it to be 7 – 12.
- “Using velocity for load development is a moot point”
- Velocity should not be seriously looked at till afterward.
43:40 Miles recommends buying a whole barrel life’s worth of components if you can.
44:50 This (Hornady’s podcast advice in this context) applies to plate matches.
- This does not apply to F-Class
- This does not apply to BR
- This does not apply to ELR
- They would reevaluate their methods past plate matches and practical long range shooting.
45:21 Jayden then took his turn on hunting rifles.
- Similar to Miles, picks a powder with known good reputation
- Sets a cut-off line for distance capability in his mind up front.
- Picks the bullet based on the job and distance expectation at the lowest expected velocity to perform down range and the bullets lowest terminal velocity then works back to what the muzzle velocity needs to be.
- Focuses next on which of the powders that can hit those numbers are known for precision.
- Avoid going to cheaper or less popular powders, wait for the right powder.
49:00 Test the load the way you are going to use it
- Magazine length if important to feed.
- 3 shot groups if necessary to avoid overheating button rifled barrels
- Test on multiple days if necessary
- Let the gun cold soak to simulate hunting days
- If the recipe doesn’t pass your expectations and criteria, try to change one of the components, whichever is the most obvious option.
- Between bullet or powder, will also consider changing to a lower BC if necessary, for example he changed ELD-M to an ELD-X in one rifle “and it was awesome”.
51:20 Discussion of group shape
- Jayden – groups should be round in short range tests.
- Linear stringing is usually a sign of a hardware problem like loose screws, actions, or stocks.
52:50 Miles stated that almost nothing hits dead center. The statistical distribution looks like a volcano with a dip at the center of the group.
54:15 Miles on group metrics
- Group size versus mean radius or SD
- He prefers the mean radius
- He likes to estimate a capability at +/- 2 Sigma
- Prefers not to rely on just the ES or group size alone.
56:00 Jayden’s take
- Group size only uses outer shots
- Mean Radius uses more of the data
- Looking at all of the data is better than looking at just the two outer ones
59:00 Discussion of CEP and other group metrics that use more of the data.
60:00 Discussion of future topics
- Chamber designs and jump sensitivity of bullet designs
- Barrel Tuners
End of session.
Either way, you can't take this stuff too seriously.
