paulsharvey
Elite Member
So, Book length is either 2.245" or 2.260" depending on source, but those lengths jam the bullet Hard into lands. As in, beat the bolt closed, and the bullet stays in barrel, to be beat out with a cleaning rod, kinda jam. 2.100" is out of lands by approx 0.050". What your describing, with a long throat, is absolutely the case with my .270Win.If your recipe specs 2.100" COL and no factories shoot well either, consider that you might have a 'long throat/leade'. Anything we buy is made to fit the shortest likely chamber & throat. Any gun will like certain ammo over others, and we can/do load our best for each gun. I suggest seating longer in increments up to what fits the mag and for starters will cycle manually.
Set a bullet into a fired case (slightly ovalled if need be) for a light slip fit. Chamber it and get an idea how far that bullet travels to contact the lands. Alt, see H'dy COL tools, ogive (.. and case bushings, shoulder length/setback when sizing, verify with head-space gauges if you have 'em) They're 'comparators' and a fired case is the easy chamber gauge vs casting one. (Just for COL this time if at all)
I do a lot of workups from a 'mid' charge (~5%,max) of a recipe because I'll tweak COL early-on and typically seat farther out. That drops pressure, and not all powders 'reduce' well. (If you seek reduced-recoil loads/powders see Lee's 2nd ed or revised (4198 y'know) for those that will and OR recent Speer manuals w/5744) Only ever had to seat deeper to fit a mag or to cycle but not with any of my own few dozen rifles/calibers.
A nice thing about ARs is that barrels aren't too pricey and swaps aren't rocket science. If a guy no DIY, .. who doesn't know someone who'll hook them up just to prove they can do it. (Dare 'em to do it right, for the best rate.
I dont have a bore scope, but I do have an endoscope, with a 9mm'ish camera. I probably should look at chamber, and see if there is a nasty burr or something, or if the chamber really does require some bullets to be seated 0.150" shorter. Don't know why I haven't tried that yet.