Cast .223 boolits in a 1 in 7 twist barrel, and general 5.56/.223 reloading advice

[7Acres]

Hello gentlemen. I feel I'm in a bit of a pickle with the AR I own when it comes to cast boolits and the assortment of reloading components I've got. I've got a couple of questions but let me give you some facts about my situation first. The 16" barrel has a 1/7 twist. The gun has a selector at the end of the gas tube to let me switch from normal pressure delivered to the action vs slightly higher pressures (for cold weather or very dirty conditions). It's a Sig 5.56 rifle. I also have a theory the selector can be thought of as switching from .223 pressures to 5.56 pressures; but I've never seen any documentation hinting at that concept. Anyway, most of the brass I have is 5.56 brass but the primers I have are*REM PRIMER 6-1/2*SMALL*RIFLE. I was given advise that 6-1/2 primers are fine for .223 but not the best for 5.56. To make matters a bit more dicey I've heard that my powder, H335, is great for .223 but not the best for 5.56 either. So all that to say I feel like I've got the components for reloading .223 but almost all of my brass is 5.56. So here are my questions 1) can I load a typical .223 load of H335 into my 5.56 brass with 6-1/2 primers and be perfectly fine? And 2) Am I going to have a real tough time getting cast boolits to pan out for me with my 1/7 twist rate? I know small cast boolits can be a challenge to start with. So far I haven't tried reloading any of my .223/5.56 stuff I bought *because I'm on the learning curve and working with my pistol components currently.*

My goal is to be able to cast for my 5.56 because it is so fun to shoot and very accurate with the j-word stuff I've been shooting so far. While I'm at it I might as well throw one more question in here. I'm under the impression that the only difference between .223 and 5.56 brass is that 5.56 brass has a thicker case wall than ..223. And all the outside dimensions are identical between the two meaning the internal case volume is smaller for 5.56 resulting in higher pressures generated from

[quilbilly]

I would doubt, with that twist, that you will be able to push a cast boolit fast enough to operate the system. My mini14 won't function at any velocities much under 2500 fps and it has a 1/10 twist. Others have written that, with a 1/9 twist, they couldn't get accuracy beyond 1800 because the boolit began key holing. Every firearm has a different personality but you should be prepared for the possibility that you won't be able to use cast. I would suggest start an experiment with cheap FMJ boolits downloading until you start "stove piping" empty cases. Definitely let us know what you discover for our own education.

[youngda9]

1) can I load a typical .223 load of H335 into my 5.56 brass with 6-1/2 primers and be perfectly fine?

In general the 5.56 nato brass is thicker therefore it has less case volume, and therefore increased pressure with the same powder charge(all other factors being equal). The powder charge has to be adjusted.

[7Acres]

Okay, so I would be a trail blazer if I were to attempt using cast boolits for this gun. I guess I'll stick with j-words for now.

So as long as I work out a lighter load than typical for .223 with H335 I can essentially use my 5.56 brass at typical .223 velocities?

If so, have any of you tried this and know how many grains of H335 I should try in my 5.56 brass?

[nighthunter]

Military brass may be thicker with the larger calibers but I believe the 5.56 cases can be used without this "problem". I have read that the 5.56 cases are nearly identical. Keep in mind that with small capacity cases including .223 have mfg. to mfg. differences that will effect performance. Even within mfg's. there are lot to lot differences. A good reloading manual will tell you how much powder to start with. If you don't have one I suggest you pick up one or two. There is no "best" that will cover all that we ask our firearms to do. Part of the rewards of reloading is finding what works for our particular firearm.

Nighthunter

[35remington]

A cast bullet can easily be pushed fast enough to operate the gas system, and at the normal setting it will function at quite low velocities, as in the 1800 to 1900 fps range with a 55 to 60 grain cast bullet. Not a problem. Have at it and do not fear. It is easily done.

You would not be a "trail blazer" as many, many users here operate an AR with cast. As do I. To the contrary; you would be following a path well tread by a lot of us.

H335 is as suited for 5.56 as it is for 223. M193 ball duplication is found with 26.5 grains and a 55 grain FMJ or SP. This is a well tested load; Lyman's max is 27 grains. 26.5 gets 3100 fps from my 16 inch M4 type AR's.

[7Acres]

Thanks, 35rem for the light at the end of the tunnel! So my 1/7 twist shouldn't pose any undo difficulty?

[saint_iverson]

35, can you provide more information regarding your cast boolit choice of preference? Alloy, gc (y/n), design (mold I.d.), manufacturer, sizing, boolit drop wt, etc.

Thanks!
Clint

[Larry Gibson]

Thanks, 35rem for the light at the end of the tunnel! So my 1/7 twist shouldn't pose any undo difficulty?

The twist will make it difficult because to get a reliable functioning load you will be pushing the RPM quite high even at 1600 - 1800 fps. A slower twist won't hit that same RPM until a much higher velocity is reached. Out of my 12" twist AR wit 20" barrel for example with the 225462 over RL22 at 2300+ fps I get accuracy equal to M193 ball with perfect functioning. Same load out of my 7" twist AR shoots improved cylinder patterns.

Do a search and you will find many post where a 7" twist AR with cast is fraut with "difficulty". I suggest a 55-60 gr cast with GC of course; the 225462 and MiHec 60 gr NATO work for me. Use easy to ignite medium to slow burning powders such as; 4895, Varget, RL19, AA4350, H4831SC or RL22. With any using less than 80% load density a dacron filler will be benificial.

The Rem 6 1/2 primers will be ok with the lower psi cast bullet loads but Rem 7 1/2s WSRs or CCI 450s are recommended for H335 loads with jacketed bullets. My standard AR load is 26.5 gr H335 under 52 gr HPs or 55 FMJs BTW. I have fond no appreciable difference in .223 or 5.56 brass of US make in 40+ years loading this cartridge. Some commercial cases will have less capacity than milsurp and some more than milsurp cases....just depends on the make and/or lot.

Larry Gibson

[Plinkster]

I run a 52gr jacketed bullet in my .223 bolt rifle using 27gr H335 in 5.56 brass with excellent results. Have at it and just start low and work up with your powder charge.

[eck0313]

Do not use the 6 1/2 primers with jacketed loads. They are for "Hornet pressures" - 40K psi. H335 works great in the 223/5.56. I've been told 10 gr. SR 4759 with the RCBS 55 gr gas check bullet shoots well @ 100 yds - no personal experience, sorry.

[runfiverun]

y'all need to read around a bit more.
the AR has been discussed 3 times in the last week.

if you can cast and load cast properly you can shoot it in anything out there.

i'm stealing a line from 44 man here.
sit and think about what it is you are trying to do,and why it will or won't work.

[GabbyM]

There’s a lot to be said for installing a screw adjustment in your front gas block to shut off the gas and run your AR-15 as a single shot straight pull with any reduced load. Then run 6 grains of unique or similar powder at around 1,700 fps in that 1:7 twist AR. No dents in your case mouths is reward enough for pulling a lever. That velocity will shoot great out to 100 yards and any increased wind deflection simply gives you training as if you were shooting a longer yardage but you don’t have to walk so far to check your target or have a mega bucks spotting scope to see the holes.

From my 1:12 twit bolt gun and AR I shoot 14.5 grains of H-4198 under the Lyman #224646 for 2,123 fps. That shoot fair from my 1:9” twist bull barrel but I only shot a couple groups just to see what would happen. My 1:12” twist bolt gun will shoot them at well under one MOA and the AR shoots them better than M198 ball out to 200 yards. Under 2” at 100.

With the small load of shotgun powder and manually operating your bolt you actually can run long strings of fire without heating up your gun thus at the end of a session have more rounds down range than if you had full cycle capability. Unique and 2400 are popular in the 22’s. What you’ll have is a 22 WMR equivalent load per velocity but with a 20 grain heavier bullet.

Before I cast lead 22 bullets I would keep some 40 grain Sierra Hornet jacketed bullets loaded up over 4.0 grains of Unique in 223 for small game loads out to 80 or 90 yards. Booked at 1355 fps. 10.0 grains of 2400 yield around 1981 fps. Those loads are from a magazine page I’ve stapled inside an old load book. I think they are from an NRA rifleman magazine but could be from any of the 1970’s magazines. Utility of them is. With my Rem 700 Varmint rifle in 223 Rem and it’s 6 ½ x 24x scope I could shoot one hole ten shot groups at fifty yards. During summer when crops are up that range covers everything inside standing fields around about any farm. I an take pigeons off a roof top with confidence of not creating a leak. I don’t like pigeons around since a coworker almost died of a disease carried by them. Plus they fry up pretty good.

Don’t know how much velocity a Hornet bullet would stand up to from a 1:7” twist but the 22 WMR loads shod be OK. Just tape a ballistic chart with scope dial settings on your ammo box. With my varmint weight bolt gun there was no scope adjustments to make. Slow bullets just had a shorter zero point. Not much vibration in a ten pound gun.

I have a Dillon progressive loader that will push out 350 rounds per hour. Using a Lee collet neck sizer no case lube is required and you can run fired brass right from the bucket into the loaded round box. You can use a die grinder AKA Dremal Motto tool with stone to grind a taper into the sizing collet. Creating a flared neck. Allowing seating of cast boolits at station three. I know with my cast boolits I’m under 22 rim fire cost. Not figured the cost when using light Hornet bullets on top. IMO you are far past 22 WMR or even the highly promoted 17 RF caliber. In performance on paper or small game. Especially with my 60 grain cast boolit load at over 2,100 fps.

Punching 22 holes in paper at 100 yards isn’t that hard of a gig to play. Not much sense in burning your barrel throat out by shooting 600 yard loads at 100 yards.

What it comes down to is do you have the time during the week to cast a few boolits to shoot on weekends or do you have to buy them factory made.

[runfiverun]

Gabby
i'm stealing that 4198 load to try.
that will make a nice ground squirell load with my soft swaged boolits.
i'll try it in the 1-7 bbl in the spring too.

[Moonie]

H4895 makes for a great reduced powder cast load as you can download it by 60%, can get my sons 5.56 mid-length gas system to cycle with 55gr or 60gr boolits using just 16gr. H4895 produces a large volume of gas as the 4895's were developed for gas operated firearms.