I'm getting ready to test fire my first 60 handloads for my Bushy Carbine; 3 Loads of 20 starting at recommended min. and moving up to a load below max, in this case myhottest load is 25gr H335, w/ 55grFMJ, pretty standard loadingI've read.

To the point: I'm using an RCBS precision mic gauge(.223)for what is a5.56 rifle. Fired formedbrass is registering .006, which according to RCBS is within sammi specs, minimum Saami will register .000 and max will read .010, so my chamber is .006 above min, but well within tolerances according to the book. I read that NATO chambers are more generous, so this didnt concern me, at first.

What nags me is this: Factory ammo headspacein the mic gauge usually reads below min; for example, Fiocchi and Remington are around -.001 - .003 below minimum, Hornady reads .001 aboveand my handloads, which were sized w/ a small base sizer die, arethe lowest at around -.004, but much more consistant than the factory loads. I've fired the above factory loads w/zero issues, but I have yet to fire a handload.

I'm crappy at math, but from my calculation my hanloadedbrass will be stretching/forming a full .010 with my handloads, is that too much? Safety is my primary concern;all my loads have been trimmed to 1.750, and the bullets are seated at 2.220 with a lite roll crimp on the cannalure. I've been very carefull to follow the manuals. My only worry is what might be excessive headspace.

Should I be concerned about excessive headspac​e, possible case head separations, or even kaboom, or am I within safety tolerances?

From what I'm readingin your post you should be ok.....20Gr sounds a little on the low endso don't be surprised if it doesn't cycle the action a few times....

Your headspace sounds fine also as long as you full length resized them with that small base die and trimmed to 1.750 as you say......"Fire Forming" is actually applicable to bolt action rifles where you use(d) the brass in just that gun, Then only have to "Neck Size" the cases.......In autoloaders you must "full length" resize.

OAL sounds ok too : 2.260 is the recommended Maxso that the rounds will fit into and feed from a magazine, Your load data and cannelure dictates where you've seated them......Sometimes you can push this out a little(Especially in bolt actions) till the Ogive/bearing surfaceof the bullet is just barely short of touching the lands - Some rifles will have a "Sweet Spot" that enhances accuracy.

When it comes to crimping the bullets I don't find it necessary nor do bench rest shooters either......Neck tension is usually sufficient to hold the bullet in place and avoids deforming them - But it's ok to just lightly "Kiss" them into the cannelure.

You should be fine.

I kinda figured it would be o.kfrom my research, these are my first handloads ever, so you can understand the pre-fire butterflies.

I thinkyou misunderstoodthe part about my handloads...my loadings(using H335)actually start at 23.6gr then 24.3gr and the hottest at 25gr, I've loaded 20 of each, but 20gr of H335 is bad mojo in the book. Easy to misread my post.

I figured I start at the Sierra manual's min. load(23.6) and work up to the 25gr of H335; it seems from my research that charge with that powder and a 55gr bullet gets good results with most who use it. Not a book max, but within .5 - .7 gr depending who's data you look at.

I only plan to crimp bullets w/ a cannelure, but w/ my current setup it seems the crimp is barely noticeable, but it's crimped, just about dead center in the cannelure.

You got any pet loads using Reloader 10x(RL10X)? I've got myself a pound, but havn't found any AR specific loadings for it. Everything I've found is for a 24" barrell w/ a 1:12 twist.

Thanks!

Yep.....​I miss-read the 20 GrainsPart - 23.6 Sounds like a good starting point, And 25 sounds like where you'll end up for best results with ball powder.

Here's a link to a burn chart : It basically lists the powders in order fastest - Slowest........

http://w​ww.ramshot.com/powde​rs/burnrate.php

You'll notice Alliant RL 10X is very close to Win748(Very common in .223-.308) and your H335 is very close to a new powder I'm using called Ramshot TAC......THIS IS FOR COMPAIRING BURN RATES ONLY !!!....Just because there's no data doesn't mean it can't be done.....Call Sierra :1 800 223 8799 and they can tell you.

Sorry...​.The only pet loads I have are for Match Ammo :W748or Vihta Vuori N540 using 69gr HPBT - Usually just buy the 55gr FMJ Stuff.

Good luck and good shooting !!!

I got a chance to test out my handloads. Everything went well. No signs of over/under pressure, no signs of anything that would cause concern. They all shot well, fed well, and extracted with ease;only my lowest load of 23.6gr H335 failed to shoot tighter groups than my control group of factory loads.

I shot two ten round groups per load,ten from a cool barrel the next tenfrom a warm one; then I would let it cool, boresnake the barrel and then move to the next loading. I dont know if all that is necessary, but I wanted as few variables as possible. I got lucky and there was almost no wind.

The tightest groups were from the hottest loading of 25gr.I mayexperiment with some other loads withsome other powders, but I think25gr H335 is my go-to loading for my 55gr bullets. Now I can finnally load up some plinking rounds in bulk, time to unpack the powder thrower...