AR15 with Lee C225-55-RF mold - terrible groupings

[35remington]

The shorter the bullet, the less spin it needs to stabilize. Thus the shorter Bator will stabilize at lower speed than the longer RCBS clone in the same (probably 1-7 to 1-9) twist barrel, but in any event a fast twist AR will stabilize either at speeds that cycle the action. Neither will be "overspun" at speeds likely to give good accuracy for persons just starting out in using cast in AR's. That means.....slow it down.

Here we want "easy" at first, not "advanced." "Easy" is found at a speed that just barely cycles the action and locks the bolt back on an empty magazine, the point being good practice loads that have reasonable accuracy. My own AR's will cycle with a 62 grain bullet at only 1800 fps with around 15 grains IMR 4198 or 17-18 grains H4895. Since powders of this speed are sensitive to position in the case, and shifting position with powder will vary velocity, and varying velocity may prevent the gun from cycling reliably, when flirting with the low end and "easy" results I use dacron to keep the powder in one place.

Velocities may vary up to 200 fps with shifting powder position. Powder forward may result in a failure to cycle when the same amount of powder to the rear near the primer may give perfect function. When the round slams home it tends to throw the powder toward the bullet (forward).

LLA tumble provides ample lube, especially when considering match shooters often lube only the portion above the gascheck and nothing else on the bullet, even at 2700 fps speeds. I sometime tumble lube myself and have no issues doing so.

Stay away from that velocity vicinity and reassure yourself you can make the gun function and shoot decently at a much lower speed first. Walk before you try to run. Try some extruded powders as well.

[6622729]

UPDATE:

Had to have hand surgery so my testing was delayed.
I reduced my powder loads in order to reduce the speed and found the groupings getting smaller, but still terrible.
My best 5 shot group was 1-1/2 inches at 75 yards (with one flyer) but it would not cycle. I had cycling issues at 16.0 and 17.0 grains as well. Groups were 5-6 inches in other tests.

At this point I do not know what to do.
Perhaps jack up the BHN from 20 to 30 and retest?
Different powder?, but I do not see why that would help.
I do cull out any cast bullets that do not look good.

<sigh> Shooting Lead Cast bullets for rifles is more challenging than I thought it would be.
Suggestions?
Thanks

You definitely do not have to go harder alloy if you're already at 20BHN. Get under 2000fps. As for 1.5" being a terrible grouping at 75yds, unless this thing is clamped down, I don't think that's terrible, especially from an AR.

[Rizzo]

cut the bhn and weight sort.
you can get that boolit up over 2700 fps but you can't slop it.
pay attention to the target..
everything matters.

Thanks for the suggestions.
Ok, I'll try BHN of 15 and see how it works.
But, my logic tells me a softer bullet would deform easier than a harder bullet and add to accuracy problems.
BHN 0f 15 sound OK to you?...or lower?

[Rizzo]

You definitely do not have to go harder alloy if you're already at 20BHN. Get under 2000fps. As for 1.5" being a terrible grouping at 75yds, unless this thing is clamped down, I don't think that's terrible, especially from an AR.

Yes, I could live with that 1.5" grouping but it would not cycle at that powder amount (16 grns. on Win 748 @ 1620 fps avg.)
I also had cycling problems up to 17.3 grains @ 1750 fps.

Looks like my next step is to lower the BHN and retest.
Then I'll try some other powders (BLC-2, 4064, 4227...)
Persistence!!

[runfiverun]

15 is about where I am.
your not gonna cycle an AR rifle until you get to the 19 gr level. [of 748 or 4895]
they run on gas volume.

[Moonie]

We have only 1 5.56 upper in the family (we prefer other calibers) and it runs 50-55gr boolits with 16gr H4895 with an intermediate length gas system.

[Roha Waha]

Google the Internet for an article called " why grown men cry " it has much information on casting and shooting. 223/5.56.

[runfiverun]

or just roll the mouse wheel down a few inches and click on cast pics.

[Rizzo]

I read in this thread "...everything matters..."

So, I am getting ready to start my next phase of load testing for my lead cast Lee C225-55-RF bullets.
I've casted the bullets with a lower BHN (approx 14 from previous 20), visually culled any that didn't look right and weight sorted them.
My cases are all under 1.750" so I chose not to trim them. They range from 1.739" to 1.744". I sorted those also by length.
Since I tumble lube with Lee Liquid Alox I was wondering if after I seat the bullets, would wiping off the lube on the exposed bullets help in the groupings?
Perhaps the lube may be adding some imbalance and causing a not so straight trajectory?

Looking forward to the next shooting to see the results.
Hopefully I see some improvement.

[Super Sneaky Steve]

Anyone here have an AR15 with a high round count of cast boolits? I know lead can build up in an AK, wondering if it's the same with direct gas. I don't want to scrub lead out of hard to reach places.

Thanks for any feed back.

[JonB_in_Glencoe]

http://castboolits.gunloads.com/show...st-Bullet-Test

[KrakenFan69]

I have somewhere near 1,000 but I Hi-Tek coat so that may not fit your question. I have no leading signs. Carbon I fouling I get. But that's another story.

Kraken Fan #69

[BHuij]

I'll preface this by saying I have theoretical knowledge only (haven't cast anything for my recently-finished .223 AR build yet).

But from what I read, the trick is getting the boolit to shoot soft enough to group well (with most people agreeing that the 1900ish FPS mark is where the boolit stabilizes best, depending on alloy and a few other factors), but hard enough to cycle the action.

There are parameters you can change to help find the right balance here:

1. Boolit hardness. If I understand correctly, harder boolit = you can push it harder before you lose all your stability and therefore accuracy. This is assuming of course that you're doing a good job culling out boolits with bad casts (wrinkles, voids, etc.)

2. Lubrication. Powder coat seems to be the best bet if you want to push it harder.

3. Buffer spring strength. A weaker spring should cycle your action more reliably on softer loads. However if you go too soft, you might be in a bad place to use factory loads or jacketed reloads.

4. Powder. Faster burning powder = sooner and usually higher peak pressure. Slower burning powder = increased potential to get an incomplete burn before the boolit exits the muzzle, depending on barrel length, charge, etc. Incomplete burn leads to more fouling than usual. TBH I'm not sure if a faster burn would help you cycle more reliably at the equivalent FPS, or make things worse. I still haven't picked a powder to try haha.

Good luck!

[Grmps]

I'd make sure the barrel is clean before starting each load group on the ladder test.
RCBS recommended straight linotype for their 223 molds.
Pc does help but is not a cure-all.
You could try putting in a larger/or adjustable gas block to improve cycling with lighter loads.

[Lloyd Smale]

ive fooled with the same thing with the same bullet with the same results. I tried the pc'd, conventionaly lubed, conventionaly lubed and pc'd. Ive tried them with ww, water dropped ww, 5050 lino/ww and straight lino. Sized to 225 and 227, shot it 1-7 1-8 and 1-9 twists all with about miserable accuracy. Now I can keep them on paper at 50 yards so in a shtf senerio a guy could use them if it was all he had but that's about it. All the advice to slow them down is fine in a bolt gun but like me hes shooting them in an AR and I'm sure would like to get them to run semi auto and that takes 2600 fps in my 16 inch guns to do it a 100 percent reliable in all 5 of my 5.56 ars. Bottom line is I think were just asking to much of a cast bullet to stand up to those pressures and twists. I just gave up and bought a couple thousand more ball bullets. Like I said I still have a coffee can of them just in case but it sure wasn't a success. Just like my attempt to run 100s subsonic. I tried every powder in the cabinet and found some loads that came close but just about all of them needed just over subsonic to run the gun. Bottom line is cast and ARs can either be said to not work well together (other then my beo) or to much work for the slight chance your going to find something that's going to work. If you want to run cast in an AR step up to at least a 300 blackout.

[Larry Gibson]

The Lyman 225415 along with the RCBS and Lee clones suffer from to little bearing surface and too much unsupported node. However, in my 12" twist AR, M70 and M700V that bullet design shoots 2 moa or less running 2250 fps at 100 yards. In my 9" twist AR and Savage Competition the same load is lucky to hold any "group.....more like "improved cylinder". All bullet holes are nice round caliber size so stability is not the problem. In the 12" twist run the RPM is 135,000. In the 9" twist the RPM is 180,000........funny how that works........

[bruce drake]

Larry, Have you tried Mihec's heavier 69 and 75gr molds yet in your AR rifles? I have the 69gr mold and I was getting an average of 3.0" at 100 yards with them through both 20" 1-7 and 1-9" AR Uppers with a load of 23.5gr of IMR4831. I need to start experimenting with this bullet and caliber again now that I've figured out the PCing process to see if that helps also.
http://castboolits.gunloads.com/show...gr-but-oh-well!
Bruce

[leadman]

I posted several years ago about my experiments with Hi-Tek coating and the 223 Rem. I was heat treating lino and doing a modified baking of the HT with water quenching after baking. My bhn remained around 30. I used Hornady copper gas checks in my successful loads in which I obtained over 3,600 fps in my 23" Contender barrel. In my AR these loads still obtained 3,000 fps. Accuracy at this velocity in both guns ran around 2 1/2" at 100 yards. There was "debris" left in the barrels with build up after 5 shots to affect the grouping but brushed out with one pass.The amount of H4895 I used was beyond what was listed in the manuals but was done to test the bullets only.
If I held velocity down to about 2,700 to 3,000 fps accuracy improved to the 1" to 1 1/2" range with no debris.
I also have been shooting a Contender 21" 22 K Hornet for at least 20 years with cast with excellent results.

My recommendation is to change your lube to either Veral Smith's Blue Soft or Lyman's moly lube. Both can be applied by hand before sizing. Change the bhn of your alloy by using linotype or heat treating. I chose lino because it casts the little bullets so much better. If you want to shoot to full jacketed velocities heat treat the lino. Weight sort to + or - .2 grs. Use only visually perfect bullets and Hornady copper gas checks. I size to .225" for both guns. Also make sure you are not shaving any lead off the bullet when seating. A Lyman neck expander die works well for ensuring the bullets are seated undamaged.
I do not shoot any jacketed bullets if I am going to shoot cast in the same range session thru the same gun. If you do I recommend you clean the barrel before trying the cast if you shoot jacketed first. This seems to be more of a factor with the 22 caliber than larger calibers.
The 22 caliber cast bullets are very finicky compared to larger calibers so everything needs to be just right.

[marek313]

The 22 caliber cast bullets are very finicky compared to larger calibers so everything needs to be just right.

This is exactly the reason I purchased another upper in 300 Blackout. I wanted to use cast in my AR but after reading many failed attempts I changed my mind and went with the 300 which is way easier to cast for. I only use FMJ in .223 considering the price I dont think its worth messing with cast.

[Larry Gibson]

Bruce

No, I have not tried the heavier bullets I cast myself yet. I've had a MP 227-65 for some time but haven't gotten around to it yet.....too many other HV irons in the fire. A couple years back leadman gave me some of his heat treated Hi-tech coated 225438s to test with 4895. They were harder than woodpeckers lips! I found they did very well up to 26-2700 fps if also lubed with a conventional lube....I believe I used 2500+ on them.