Looking to cast for 300bo

[aquarist]

Recently I bought several AR lowers and I want to build a 300bo so I can cast for it. In all honestly I haven't done too much research into the topic yet but wanted to start this thread so I can have a centralized place to ask questions when the need arises. I am wanting to shoot subsonic with the most affordable reload possible, I have plans to buy a can later in the year. I've seen some awesome hollow point projectiles but not sure the cost of the hollow point molds, and aren't most hp molds single cavity? Hopefully I can find something to do four or six projectiles at a time. From what I've read 200-220 grain projectiles work well in 300bo suppressed and unsurpassed. I'm totally new to the 300bo market, have been looking at a few uppers and came across this one:

https://22mods4all.com/en/barreled-upper-assemblies/245638-16-300aac-blackout-ar15-keymod-extended-18-twist-nitride-barrel.html#/warranty-lifetimelimitedwarra/include_a_bolt_carri-m16_nitrite_bcg_with/lower_assembl-add_a_lower_build_ki

I like the way it looks, and I know it's cheap and probably not top notch quality. Not looking for super high end for my first 300bo but want to be able to shoot accurately with my reloads, and not break the bank. A buddy did tell me he can get my a better quality upper for not much more, waiting to hear the details about that, when I do will report back with details.

In preparation for reloading 300bo I want to go ahead and get a case trimmer, and anything else I need for case prep for this caliber. I have nearly 10k .223/5.56 casings a good deal are military and will be Swaged. What's the best trimmer for trimming in bulk?

Also any suggestions on and and all things 300bo reloading and shooting related are welcome!

[Quiettime]

There's a many few ways to convert 5.56 to .300 but the best thing I've found is the 2" mini cutoff saw from Harbor Freight.http://www.harborfreight.com/2-in-mini-bench-top-cut-off-saw-62136.html. I first ordered a seemingly identical saw from Amazon but the quality of the motor on that one is not high and the saw runs erratically. For a time, the HF saws were in short supply but I happened across on in a semi-distant town. You will also need a jig to hold the cases. My jig is the "VZ58" jig http://www.300blktalk.com/forum/viewtopic.php?t=80842&start=330

Next, I highly recommend a Lyman M-Die for use with cast boolits. I use this one http://www.midwayusa.com/product/409943/lyman-neck-expander-m-die-30-caliber-short ...but found I needed to have .250" faced off the end to work with the Blk. Had it to do again, I'd probably have .260" taken off but it works nonetheless.
I also use Lyman's reloading dies just fine though others will work. Forming, I use a liberal application of the typical lanolin-based lube (think mine is from Dillon currently) but make sure you remove with some iso alcohol before tumbling.

Mold I use is http://noebulletmolds.com/NV/product_info.php?products_id=205 although mine has a HP cavity which I love as it allows use of pop rivet shanks through a baking sheet to hold them upside down for base-first powder coating

[aquarist]

@Quiettime Thanks for taking the time to type that awesome response. I am going to check out those links tonight.

[FISH4BUGS]

One thing I learned is that you should NEVER shoot lead bullets through a supressor. I have a Bowers CAC9 that I shoot with all my 380 and 9mm subguns. I shot cast through them with the permission of the manufacturer. He changed his mind after about 5000 rounds. There was so much lead buildup in the baffles that he just gutted the can, upgraded and replaced the baffles.
I shot exclusively subsonic ammo with a 5# ww to 1# lino alloy.
After his rebuilding the can, he changed his mind and no longer recommends it.
Make sure your can manufacturer says it is OK to shoot lead bullets through it.

[aquarist]

@fish4bugs That's good advice. I wasn't aware about not shooting lead through a suppressor. I'll see if there are any vendors that allow it, I was planning on using the same can for my 300bo and my AR-9, if I cannot find a lead friendly suppressor, I can always load up some FMJ to shoot through the suppressor, or get one for my .223/5.56. Right now the suppressor is fifth on the list of wants for my 300bo but still want to educate myself on them. My wants in order;

1- reloading equipment for the caliber
2- upper in 300bo
3- eotech, acog, or similar site
4- match grade trigger
5- suppressor and tax stamp

Anyone know what twist barrel I should be looking at getting? I do enjoy long range shooting and would like to eventually get a nice quality barrel, but affordability is key for the first build.

[adanymous]

I know the guy that owns the website you were looking to order from. Ive had some business dealings with him in the past. And I wont ever have again. Super shady character. My company bought a couple thousand dollars worth of stuff from his company, and I think we ended up putting it in the garbage can rather than retailing it, just to avoid attaching our name to a garbage product. Im not trying to talk trash. Just making a statement based on experience.

[aquarist]

@adantmous Thanks for letting me know. I just happened to stumble on that website and thought they had good prices but figured there was some catch either quality, service, or both. I've heard PSA has decent prices on uppers if you wait till they are on sale.

[Moonie]

If it were such a bad idea to shoot lead through suppressors they wouldn't make them for 22LR...

[dudel]

I wouldn't be shooting lead in a sealed suppressor. Even in a user serviceable can, getting lead out is a pain. PC may help.

A six cavity mold of 200+gr Boolits is going to get tiring pretty quickly.

You may want to try matching boolit boolit weight to barrel twist. That's going to be an important part of the accuracy component.

I use a HF trimmer and a jib to make up the cases. Once cut down and formed, they still need to be trimmed to final length. The HF saw and jig just get you in the ballpark. I like my Wilson trimmer for getting the cases to final trim length.

I find the bulk Hornady 150gr FMJBT to perform really will in by 300BOs. Not cast; but often on sale.

[jcren]

On the long rang shooting idea, the blackout is kind of a tough choice for this. If you get a 1-10 or so barrel to shoot hypersonic/light bullets well, it has ballistics simular to a 7.63×39. But a 1-7 barrel for heavy subs will limit cast velocity, and of course subs have the ballistics of a modest pistol round (rainbow trajectory after 150 or so). Just some observations to keep in mind.

[popper]

Decide what you want it to do. Barrels aren't expensive but the other stuff can be. I got the lyman power trimmer, HF chop saw, You'll probably need a swager to remove primers from Mil brass but I just use the universal and PP uniformer. RCBS PP cleaner is worthless.
1- reloading equipment for the caliber Lee die set works fine. Flaring tool is great also.
2- upper in 300bo Carbine, rifle, pistol? Really need to decide this first.
3- eotech, acog, or similar site BUIS or scope. IR if it is legal?
4- match grade trigger Timney 4# for field work. not sure why for subs.
5- suppressor and tax stamp Goes with #2.

[aquarist]

@Quiettime Went through your links and will probably buy that jig and the harbor freight saw, seems like a quick and easy way to trim down my brass.

@jcren Do you know of any decent resources where I can educate myself on barrel twist? I'm looking for a general everyday shooter that I can take out and have fun with. Will be shooting mostly 50-100 yards with the first rifle might try 200-300 with the budget build. Then will end up building something to do 50-500, might be a different caliber not sure, if I like the results from my 300bo build and want to invest in a much higher end barrel and parts for a semi-auto long distance rifle. Right now subsonic or the suppressor isn't the highest priority, have been kicking around buying a suppressor for a few years and have been told a 300bo is a perfect candidate. Still really new to the AR platform weapons, have five lowers to work with currently. Mainly need to learn what twist barrel shoots what grain of cast reliably.

@popper First and foremost I'm looking for an everyday shooter, since I have gotten into reloading I have been able to practice more and am considering training up to shot some comps next year once I get decent equipment. I shoot a lot and want to be able to shoot more rifle at a more affordable price. Currently my club longest range is 300 yards, but they are expanding it to 500+ in the next several years. I am planning a carbine style platform, I do already have back up iron sights but since this is a range gun not a comp gun probably won't need them. As for the site I am considering the Burris 536 because of the current rebate. The suppressor an tax stamp are least of my worries currently, probably won't even use a suppressor on the first build, I've just wanted one for a while and may try and get the ball rolling on one prior to the election.

[aquarist]

Any suggestions on molds? Have my upper on order just waiting for all the bits and pieces to come in to build it. I did not go with the upper I linked in the first post. I ordered a radical arms upper.

[popper]

I will suggest a real rifle stock, magpul has a good one. You won't shoot 2-300 with the collapsible carbine thingy. You already got the upper, I would suggest nothing faster than 1:9 - lets you go a little farther with slightly heavier than you say you want to shoot.

[Gunnut 45/454]

I have a CMMG 16" carbine gassed upper. Expensive and I don't think they offer it any more. If I were you go with a PSA decent price quality and service. I've bought a complete AR 5.56mm from them and its been a great shooting AR. Looking at the website you first posted I'd run from that setup cause it has a pistol gassed 16" barrel!! ***!

[bgreed]

Don't waste your time making brass you can but brass ready to go from blackoutbrass.com $125k plus about $15 shipping all from reworked military brass mainly LC.

For cast boolits I use a four place mold from NOE that drops a great 230gr bullet that I powder coat. Run them approx. 1050fps with 11.5 gr 5744

[aquarist]

For general purpose which of these two molds would be the better choice? The upper I am planning to order is here: http://www.radicalfirearms.com/product-p/fu16-300hbar-15fhr.htm

http://noebulletmolds.com/NV/product_info.php?cPath=30&products_id=958

http://noebulletmolds.com/NV/product_info.php?cPath=30&products_id=205

[Hamish]

aquarist,

I see you have posted interest in two different uppers, both in 8" twist. As mentioned earlier in the thread, by going to that fast a twist rate you are limiting your options with median and lighter weight bullets.

1/9 seems to be about the best choice for being able to run heavy subs and lighter super loads. Personally Im very happy with 1/10", knowing that I can push very light bullets, and with very little trouble found happiness with 165 and 195 gr cast loads.

As far as the two NOE's, the 247 heavy was adapted from the Lee specifically for the BO. The K-31 I don't know of anyone reporting using it in the BO, but I would think it would be fine. If you are still interested in it when you finish your build, consider hitting the WTB area and see about some samples.

[aquarist]

@Hamish The upper linked in the first post was something I was considering when I first start the thread, then after talking with my ffl he was able to get my a better deal on the Radical Arms upper. That's good info on the barrel twists, I have been trying to find some decent information on which twist is best for using cast. A buddy that lives close by uses the 247 grain mold and it works well in his 300bo, going to try and get some sample projectiles form him. Good idea as well about posting the wtb for some samples, might go do that now and see if I can buy 100 or so of the K-31 projectiles as well.