No i deer Posted November 6, 2017 Report Share Posted November 6, 2017 A shooting colleague told me the other week that his ES's halved from using a muzzle brake to a moderator.it's not something I've tried but can this happen and how/why. No i deer. Link to comment Share on other sites More sharing options...
Catch-22 Posted November 6, 2017 Report Share Posted November 6, 2017 This is a guess but if what you say is true, it 'could' have something to do with pressure. using a moddy will generate a slight increase in pressure. It 'could' be that with your friends particular setup, that rifle/bullet combo likes a particular pressure range. If by using a muzzle break the pressure generated is lower, then maybe it falls out of favour with his particular setup. dunno. TBH, you see a lot of practical / tactical shooters, especially in the States, with breaks on their guns and I've yet to hear of changes in ES as a result of using a moddy over a break. could be a good test to run with several different rifles, mods, breaks, calibres etc to see if there's any correlation or truth in it. Link to comment Share on other sites More sharing options...
No i deer Posted November 7, 2017 Author Report Share Posted November 7, 2017 the rifle is a 308 steelcore cyclone I think.s5 mod.steelcores own brake.i think the load was 185gr berger jugs over n560. his es was near 40fps with the brake on and went down around 20fps with the mod on so he told me. Link to comment Share on other sites More sharing options...
brown dog Posted November 7, 2017 Report Share Posted November 7, 2017 Doesn't sound probable. I'm pretty sure the change'll be due to another unidentified or unmentioned inconsistency between strings. Eg Was this seamless back to back testing on the same day at the same temp? Same chrono? Had the chrono been moved? Switched off/on? Light condition changed (if screens)? Same ammo batch? Ie, nothing changed at all except taking a moment to swap mod & brake? I'd put money on there being a variable other than brake/mod that caused this. Link to comment Share on other sites More sharing options...
No i deer Posted November 7, 2017 Author Report Share Posted November 7, 2017 I will ask the question but as far as I know the brake was swapped with the mod.chrony was the v3 type barrel mounted chrony. Shots were fired down stickledown at 1000yds on to the new electronic targets.i will confirm this info.. I too thought it was odd but it' not something I've tried.i waste enough ammo with out doing that too. Link to comment Share on other sites More sharing options...
RePete Posted November 7, 2017 Report Share Posted November 7, 2017 Could be down to barrel harmonics in some weird way............mods are generally heavier than brakes. Did the group size vary? RePete Link to comment Share on other sites More sharing options...
No i deer Posted November 7, 2017 Author Report Share Posted November 7, 2017 Yes I believe they did but it was something like a 15 inch group with the brake and 13 inches with the mod on.ive emailed shooting mate and awaiting a reply Link to comment Share on other sites More sharing options...
brown dog Posted November 7, 2017 Report Share Posted November 7, 2017 If it was a magneto, it's been detached a reattached between strings, and, presumably, on the mod, it had a different relationship to the axis of the bore. Put that change, together with the fact that we're talking about only 10fps delta at either end of the ES, over an unknown number of shots, I'd say he's measured experimental error and normal variance between samples. Thinking statistically, and allowing for observations from small samples, his ES probably isn't changing and lies somewhere in the 40 - 80 range. Link to comment Share on other sites More sharing options...
Catch-22 Posted November 7, 2017 Report Share Posted November 7, 2017 2 hours ago, RePete said: Could be down to barrel harmonics in some weird way............mods are generally heavier than brakes. Did the group size vary? RePete I could see the harmonics affecting group size (e.g. If the break or moddy act like a barrel tuner) but I don't think that would change the ES. ES is speed, whether an increase or decrease in pressure as a result of different primers, outside & barrel temperature, charge weight and powder variations, seating depth & neck tension (seat too deeply against lands or too much neck tension does increase pressure) or using a moddy (does increase pressure too). i suspect Brown Dog is right, more likely an error in recording like for like data. However I do still consider an increase in pressure by utilising a moddy could have an effect. Link to comment Share on other sites More sharing options...
No i deer Posted November 7, 2017 Author Report Share Posted November 7, 2017 Imagine a real raincoat then double it.this man records everything . Nice bloke he likes his stats. Link to comment Share on other sites More sharing options...
RePete Posted November 7, 2017 Report Share Posted November 7, 2017 Low ES doesn't always mean tight groups.................. RePete Link to comment Share on other sites More sharing options...
No i deer Posted November 7, 2017 Author Report Share Posted November 7, 2017 Right then all the info. Rifle.calibre was correct. Lapua brass 185gr juggs N550 Fed match gold primers Magneto speed v2 Muzzle brake fitted.an average speed of 2654fps over 5 shots with an ES of 43fps.the 5 shot group was 14 inches at 900yds.elevations were decent.group size was horizontal. Same load using mod gave average velocity of 2671fps with an ES of 23fps and a 12 inch 5 shot group at 900yds. Link to comment Share on other sites More sharing options...
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