bmash Wrote:Not to hijack the thread, but to answer the 129 ABLR question, I am using H4895 per Nosler 6.5 Grendel load data. R7.5 primer, Hornady brass, 2.26 coal, 129ablr, 18 Lilja barrel AR.
26.1 gr 4 shot group of 0.66 (0.62 vert.)@2250/s
26.3 gr 4 shot group of 0.95 (0.36 vert.)@2266/s
(I dont recall why I only went with a 4 shot group! Maybe since Im running low on H4895!!)
And yes, you need to get your seating die machined to match the bullet since these are rather hard to seat to length and will put a ring on bullet. (Compressed) As suggested I will try rotating bullet during loading next try.
Also, 129 ABLR is 0.6 group in my 260 rem. This is with a trued bolt action and match grade barrel.
Thanks for data!
Rotating the case while seating definitely helps with runout, however, Im hearing more and more that concentricity is not as important as one might think. Several thousand's either way doesnt seem to have much effect on accuracy. I chased it last year, got serious about it and while my concentricity improved, I couldnt really see a definitive difference downrange. And I recently heard Eric Cortina, the 2023 SW National F-Class champion and 2023 International F-Class Champion, say he doesnt even check for it anymore. Its just not that important compared to the powder/primer combo, neck tension, using quality components. Not saying not do what you can within reason to improve concentricity, just saying Im not sure youre going to see much, if any, improvement on target after you do! Having said that, little to no runout does make me feel better!
