New to cast boolits with a blackout question

[Crytes]

I've built an ar15 for supersonic use only with a 1 in 11 twist. I'm using the lee 312-155 mold and acquired IMR 4227 powder as I've seen blk out loads using it later to notice that my weight falls into a dead spot on the data I find. I have 2 questions first I've seated 2 dummy rounds to check magazine fit and feeding and it works but in order to clear the rib in the magazine without upsetting the round I've had to seat to near minimum over all length. Does this sound right or am I doing something wrong? Second with an actual bullet weight of 161 +/-0.5 grain were is my lower limit powder charge to not worry about lead lodged in my barrel? BTW these are lubed sized to.309 and gas checked if that effects my numbers.

[wcp4570]

Crytes
First off, welcome to the forum. I am shooting the blackout in an AR using the same boolit with gas check and H110. I seat my boolits to the crimp groove and they are shorter than the mags. I started my load development with a lite charge and worked up to a load that was fully functional. The load is 14.5 grains H110 and average velocity is 1705fps. I did not have any leading with this load. You should start load development on the low end powder charge and fire a few rounds increasing the charge .3 or .5 grains until you find a load that works in your gun. Good luck.

wcp

[MT Chambers]

While I know nothing about the AR. I'm sure the action will fail to operate well before there is any chance of a stuck bullet.

[Crytes]

I'm sure you're right chambers but even if the action doesn't cycle I want to avoid pounding a boolit the rest of the way through I just wanted a good low point to avoid that and work up until either I get function or pressure signs. This is my first rifle build and I am new to reloading and casting so I've got much to learn and this seems like a good place for the reloading and casting part.

[Wayne S]

Since you have direct access to the chamber, use one of your as cast bullets to slug your throat. .309 seams a tad small especially for an auto loader

[Crytes]

is that the technique I was reading about with the lead filled case behind the boolit and pounded from the muzzle until it bounces? still learning about slugging and haven't done any of it yet so you may very well be correct. The .309 was a guess at being .001 over published size being enough.

[Jupiter7]

For reference, I seat that bullet to mid-cannelure. It feeds and fires in all mags.

[Crytes]

just slugged my bore still looking for a good way to do the chamber at for the bore the slug that traveled the length of the bore and the one from the muzzle end bother measured 0.3075 at the widest point so it measures tight. However it feels looser from the about gas port to the muzzle not sure what to make of that.

[KYShooter73]

I'm at the same point you are. I'm just waiting on my .309 sizer die. I bought some lil'gun to try first. My bore slugged right at .307. I'm going to try a .309 powder coated and gas checked. Hopefully I'll be firing live rounds down range this weekend.

[Crytes]

I got a few gas checked ones made up and waiting for me to make it to the range. powder coating interests me too but don't got the stuff together to try that yet.

[Moonie]

I'm at the same point you are. I'm just waiting on my .309 sizer die. I bought some lil'gun to try first. My bore slugged right at .307. I'm going to try a .309 powder coated and gas checked. Hopefully I'll be firing live rounds down range this weekend.

.307 measured with a caliper or micrometer?

[KYShooter73]

Caliper, I don't have a micrometer.

[Moonie]

Caliper, I don't have a micrometer.

Calipers are not accurate enough for this kind of measurement, take the result with a grain of salt. But the .309 sizer should be fine for you. Some use larger, if I use a .311 I have some chambering issues with my upper, but my sons upper has no issues.

[xacex]

I had a .308 sizer I bought when I just started casting. Not much good as I found out, but I honed it out to .310 which for some reason Lee doesn't make. It is a good size for both of my blackouts. I had the same problem as Monnie with one gun not accepting the .311 sized boolits.

[Boz330]

My BO takes the 311 sized boolits just fine and the 309 don't shoot as tight a group.
With powder being tough to get I tried a couple that I have in stock that gave me pretty good results with the Lee 155gr. One was AA2230S, AA2230, and 748. I haven't been able to locate any AA1680. Lil Gun didn't do very well for me.

Bob

[KYShooter73]

What kind of OAL are you folks using? I have mine up and running, including bolt lock back. I am having some magazine problems and jams due to the rib. Im using the Lee 312-155 referenced above, sized .309, then powder coated, leaving diameter around .311 and seating to the bottom portion of the cannelure. I think it was 1.997 or something like that, Im at work at the moment.

My first batch after getting everything functioning was MOB accuracy at 50 yards (minute of barn). I didnt gas check and was pushing them pretty hard. Probably around 2000fps. Hopefully the gas check will bring them in where they should be, otherwise I would be better off throwing rocks. If the rain allows I will run them through the chrony tonight and see if the GC helps my accuracy. I hope Im not having some kind of RPM issues screwing me up. I would really have to fall back and regroup.

[KYShooter73]

Ah-hah! Gas check made a world of difference. Was getting dark, off hand at 50 more the size of a tennis ball than a barn. Load was too hot also.....primers blowing out...primer anvils and Gisselle triggers don't mix well FYI. Gonna size on down to .309, seat a hair deeper, and retry with the lower power load. Hopefully sizing down and seating deeper will cure my magazine woes.

[Crytes]

I'm considering some pmags as the contact between the rib and the lead concerns me and in the pmag the rib looks much smaller

[Boz330]

I picked up some mags specifically for the BO and they work like a charm. Can't remember the name or where I got them but you don't have to file the rib down.

Bob

[Moonie]

I'm considering some pmags as the contact between the rib and the lead concerns me and in the pmag the rib looks much smaller

I bought a couple of pmag's, had serious issues with them due to the side ribs and the rib in the front. Caused rounds to jam, did not try with the 312-155 but with the 245/247 it was a no-go. My Lancer mags work perfectly for all my 300 loads.

[bikerbeans]

I am loading for two different AR platform blackouts, 16" 1:8 twist and a 9" 1:7 twist. The 16" gun cycles great with H110 and 150g bullets & boolits. I have settled on 15 grains with H110 for a 150g projectile. This same load works fine in the short barrel AR but throws the brass a lot further because the gas port is closer to the chamber.

Sorry I can't help you with the I4227. The only can of I4227 I have found in the last year I gave to a good friend who wanted it more than I did.

BB

[Crytes]

comparing loads that I could find that use h110 and 4227 with the same boollits 4227 allways uses a little more powder and gets lees fps and pressure so unless there is a variable I do not foresee I think I have a safe point to start using some h110 data and dialing it back a little. I'll report back tomarrow if I make it to the range

[Crytes]

good news no pressure signs between 15gn to 16gn but action only moves an inch. I'm seating to the first groove I know seating to the second groove will raise pressure is this were others are seating this boolit? Also I approaching Capacity so how fast will pressure increase from oal decrease or compression. Another anomaly I'd like to identify is that out of my 20 test rounds one failed to go bang. After extraction primer showed a definite strike. upon returning I used the kinetic puller but was confused when no powder came out. Examining the case there is a film of black soot coating the inside of the entire case and a smudge or soot mixed with lube stuck to the back of the projectile. I weighed every load so am sure powder went in but what happened to it.

[A pause for the COZ]

Your doing ok for starting out.
I shoot lots and lots of the LEE bullets. Ranch Dog sells a .310 LEE sizing die. I have a .309 die That has been collecting dust since I got it.

My two powders for this bullet are H110, and RL-7. I load both at 16 gr. H110 is a little faster fps and RL-7 is a little more accurate.

I found my .308 sizing die has a whole new job resizing 124gr fmj .310 bulk AK bullets down to .308 for use in the Black out.
For jacketed loads, I shoot H110 or LilGun. LilGun is my Hunting powder. Gives a good 100 fps more per load.

Be safe, Enjoy, Have fun.

[xacex]

Ranch dog closed his store from what I remember. I would just hone out your .309 sizer. There is a thread on how to do it somewhere on here. It is not hard at all, but you do need a micrometer.