Good first time out with cast in AR-15

[JeffG]

I've had a good experience moving into use cast in the AR, thanks to a lot of good information spread out in numerous threads on the site. Thanks to all of you!

I'm shooting an S&W M&P 15 Sport II in 5.56 NATO with a Surefire Pro Comp muzzle brake and 3 MOA Truglo red dot The first 1000 rounds have been factory Winchester 5.56 NATO with 55 grain FMJ or my reloads using Hornady 55 grain FMJ BT over H335. I ordered in the Lee 225-55-RF, some Hornady checks and after slugging the throat a .225 H&I sizing die for the Lyman 4500. I went the route of H4895, starting at 20.4 grains, no filler, CCO SR Primers and seated the bullets to 2.096 OAL. They were lubed with White Label lube. Bullets were COWW + 2-3% tin, visual then weight sorted to 55.0-55.1 grains, age hardened for 2-3 weeks while waiting on a few things. I'd started at 19 grains for 5 rounds, which cycled the action but you could tell it was a little slow and had 1 of 5 rounds that didn't feed properly. The next were at 20 grains and they cycled the action fine. Seat of the pants on some gongs at 35-45 yards was good so I loaded up some in mixed brass, all of which were prepped by deburring the flash hole, cutting the pockets to uniform depth with the RCBS tool and trimming the brass to 1.750. An RCBS 5.56 NATO SB die set was used in addition to Lee's collet crimp die and an NOE M type expander for use with Lee's Universal Expander die body.

I set the target at 50 yards and rested the front of the rifle only on a shooting bag. Here's the group along with chronograph numbers, which measured about 2.3 inches. I think I need to go back now, sort the brass for more shots and put something a little more accurate on the rifle optics wise and I expect it will do better. Maybe 100 yards this weekend. I'm pleased so far.



177701

[runfiverun]

go ahead and put some powder in the cases too.
your velocity variation is pretty high.

[TenTea]

Looks promising and enjoyable.
Hard to shoot precise groups with a 3 moa dot at 50 yards, though.
I'd say you did well.

[WebMonkey]

Thanks for the report
:)

[blixen]

Thanks! Very helpful for my haphazard approach to load development in my Triple-deuce CZ. By mixed cases do you mean commercial AND military, cause I've found wide variation in weight between commercial and military. Again, Tnx.

[35remington]

If your current average is 2.3 inches at fifty it's not brass sorting, bullet weighing and primer pocket uniforming that is holding you back. You can skip all those things and shoot the same sized groups. Go upward in bullet size if possible.

Temper your expectations of what a generous chamber autoloader will provide and you will achieve good usable accuracy given the velocity level and bullet performance.

[JeffG]

Can do, thank you. Just curious, would a little Dacron help with the variation too? I typically use some Dacron with 8x57 and 7.62.54.


go ahead and put some powder in the cases too.
your velocity variation is pretty high.

[JeffG]

I agree on the red dot. I keep contemplating one of the Nikon P223 scopes in 3x32, but haven't made that jump yet, settling instead on getting it going good with cast. I'm not disappointed.


Looks promising and enjoyable.
Hard to shoot precise groups with a 3 moa dot at 50 yards, though.
I'd say you did well.

[JeffG]

Thank you. Good things to keep in mind. Going to take a look at 100 yard groups this weekend if it doesn't rain and up the powder charge, track what that does. The throat measured about .2245 as I recall and I'm sizing to .225. At a minimum, I can try unsized and see what that does. I have plenty to do, all fun.


If your current average is 2.3 inches at fifty it's not brass sorting, bullet weighing and primer pocket uniforming that is holding you back. You can skip all those things and shoot the same sized groups. Go upward in bullet size if possible.

Temper your expectations of what a generous chamber autoloader will provide and you will achieve good usable accuracy given the velocity level and bullet performance.

[runfiverun]

it would.
the 19-20gr area would benefit from the Dacron.
once you go past there I'd work without it.

[35remington]

Given 5.56 chambers are rather generous I'm suspicious of your throat measurement. This would be the smallest throat in 5.56 I've ever heard of and I doubt yours is really that atypical.

If you gun will accept a larger bullet by actual trial, use it. The Dacron will help greatly and allow a lower charge for reliable function due to less low speed in the velocity swings.

[runfiverun]

I bet it will take a 227 but the drive band will scuff in the ball seat area.
this helps accuracy but impedes function.
the AR rifles have to have some compromises made here and there to get both accuracy and function.
I rely more on the nose than the drive bands in the 5.56's.
the nose shape and diameter right in front of the drive bands [in the 219+ area] will pay off better than a bigger boolit will since that is what gets everything started straight into the barrel.

now if this were a 22-250 or 220 swift then the larger diameter would help accuracy [it would also help settle the load down]
I run the same load and boolits in my 223's and the other 2 only I size 225 for the AR's and 227 for the bolt guns for this very reason.

[35remington]

If Dacron is used with bullets of larger diameter simply seat deeper so the band does not inhibit chambering if in fact the throat is small. The Dacron will prevent gas cutting if the base protrudes below the neck. I am still gonna guess the throat is not that small close to the end of
the chamber neck.

Do try the larger diameter. The as cast diameter may ultimately limit things unless the mould is beagled, in which case the nose gets larger as well. This is the only way to get close nose fit if the as cast dimension is undersized. Bore riding designs like this that may have too much nose slop will shoot poorly, certainly. So yeah, nose fit is worth looking into if you suspect the bullet nose is undersized.

But that also can be overdone to the point the rifle won't feed . The suspicious thing is that 5.56 chamber dimensions do not call for a throat as small as yours, and none of those I have measured have been that small which is why I am suspicious. The throat dimensions are usually fairly sloppy.

[35remington]

If you can quantify just how long your throat is, that is helpful as well in determining fit clearances. Seating deeper may not be necessary for all I know.

Just how did you measure this throat? Some methods are hinky as far as accuracy but often a visual is helpful anyway even if the numbers are nonsensical.

If I measure a throat I do it more than once sometimes to be sure. Often I am too lazy to measure anything and just try assorted bullet dimensions until something works in a new rifle. It helps to load on the range for this.

[JeffG]

If you can quantify just how long your throat is, that is helpful as well in determining fit clearances. Seating deeper may not be necessary for all I know.

Just how did you measure this throat? Some methods are hinky as far as accuracy but often a visual is helpful anyway even if the numbers are nonsensical.

If I measure a throat I do it more than once sometimes to be sure. Often I am too lazy to measure anything and just try assorted bullet dimensions until something works in a new rifle. It helps to load on the range for this.

i did a pound cast. I filled one case mostly full of lead till about half the neck was full, then cast a half dozen pure lead bullets. I lubed the bullet, placed it in the neck then chambered it. From there I tapped it with my Dewey coated rid till it had fully filled the throat. I expected the brass then lightly tapped the slug onto a soft cloth and measured with my mic. I think I still have the slug and spotted the case and pure lead bullets today so can always do another.

I also loaded up 10 more rounds, bumping the powder up to 21 grains. Will check that out tomorrow.

[JeffG]

Oh yeah, other no I ran another through the barrel but can't remember the values. It only takes a minute to do it again so may do it for sanity check.

[Harter66]

I load for a couple of ARs and have zero feed issues with loading out to 2.200 with the NOE variant of that bullet in and ATI Omni Hybrid . Even that rifle will hold 2.5 @ 100 . It did take me a couple of sight changes to get it together.
Taking into account that it is a bottom rung rifle in my case , I'm pleased with it. I would definitely work the OAL to see if the groups will close some . Don't be shy about taking it out as far as your mags will allow . The 6.8 I load for likes 2.285 ,it likes 2.300 even better but the mags won't let it feed .

Stretching out the OAL will lower pressures ,add case space , and get you closer to the lands and may even get the driving bands into the leade to fill it up .
There is the possibility of course that I'm wrong and none of this is a good idea .

Welcome to cast in an AR .

I did run into problems with crown fouling in the gap between the flash hider and muzzle . A spontaneous group crash makes that a good place to look .

[sukivel]

I use the NOE RCBS clone, which I think is the same bullet, over 19 grains of H335. I tested some without a gas check and powdercoated...not a trace of leading. I couldn't believe it. I don't think I'll ever gc those little boogers again!