6X45 or 25-45 Sharps in an AR

[Dutchninja]

I have plenty of barrels 5.56, 300 blackout, even a 458 Socom rifle, looking for something a bit different for my next build (The problem of having extra parts lying around again). Looking for any opinions from someone that has run one or both cartridges. I've been making a comparison sheet on an excel spread sheet to help decide but I thought I would also ask here. I'm trying not to convince myself to go even farther and go 6.5 Grendel because of the special mags, bolt etc. Thoughts? As for what it would be used for? Just to mess around with something else, some target shooting, possibly deer hunting but I have 10 other rifles for deer......

[garym1a2]

5.45x39. You can still get cheap ammo for it. You just have to modify Pmag follwers in their gen2 mags to load upto 25 rounds.
It's a nice shooting round in the Ar. Can't reload it easy so I just stocked up on a lifetime supply of ammo when building it.

[Dutchninja]

I did take a look at that round, but even with cheap surplus I'd still like the option to reload for it someone effectively.

[27judge]

go for the 6X45 I had one that was a real tack driver ,also easy to load for . tks ken

[Tackleberry41]

I looked at the various versions of the 5.56 being offered, the 6x45 etc. I did the math, wasnt any real gain for the effort. 6mm offered heavier bullets but reduced velocity, same thing you get out of the 300 AAC. You need more case capacity to push heavier bullets faster, also means modified or different mags, bolt face etc.

5.56 you can walk in and buy, 6x45 your into case forming, harder to find dies. I dont mind case forming for a single shot or bolt action, but in a semi auto its alot more work and brass is way easier to lose. At least 300AAC you can buy the brass ready to go.

[Dutchninja]

With my comparison spread sheet, I'm am seeing exactly what you are saying with the 6X45 vs .223. Might end up doing another 300 instead.

[Tackleberry41]

Yea the 6x45 was 90gr at 2540fps for 1300ftlbs, the 5.56 is 62gr at 3100fps for...1300ftlbs. Alot of effort for a .5mm bigger hole. Only way around it is something like the 6.5 or 6.8 with more case capacity.

Blackout isnt any better on the math 125gr at 2215fps for pretty much the same energy. From what I have seen of the 300 the only real thing going for it is suppressed, or being able to run pretty much a 7.62x39 in an AR without the mag issues.

The 300 is easy to replicate. I was launching 200gr cast out of my bolt action 30-30 at 1050fps, and recently 200gr cast out of a mosin for the same velocity. A friend had his recently finished 300 AR build and was really surprised how much quieter my mosin was than his. And I didnt have to worry about the powder to use. But less blast with a smaller amount of fast burning pistol powder vs the slower burning stuff needed to get a 300 to cycle.

[dragon813gt]

I've been debating which 25 caliber AR to build. The Sharps was thrown out right away for a few reasons. So that leaves 25x45 and 25-223. 25-223 allows you to run longer heavier bullets. But you have to trim the cases down. Black Hole Weaponry has been producing some very accurate 25x45 barrels. I wish the 25-223 was standardized under a name like 25AR. Then manufacturers could get on board because it's standardized. I've been tossing around building a 25cal AR for over three years now and every time I think I have it nailed down something comes up that changes my mind.

[josh82]

I would build a ar with 9mm bullets in a trimmed 223 case. It is a lot of gunsmithing required at least make a chamber reamer and threading a barrel for your ar. http://tapatalk.imageshack.com/v2/15/03/05/de718a35ff11c30e563e774ae36bddaa.jpg

[Edward]

Have several 6x45 ,one a stoner barrel 1-8 ,shoots up to 100g and kills deer very nice ! The other is a D-tec custom bull barrel 1-14 that tries to stack @ 200 yds ,also plays well @ 600 yds. Same bolts /mags based on .223 case .Get one and you will not get much trigger time on your other uppers!

[Jupiter7]

The real loser is the .223 case. Only so much it can give, regardless of the size of the hole on the end. I've been in the same caliber dilemma recently, bigger than a 22 and faster than a .300(I have 2 already). If it doesn't shoot as flat as my 75grn HPBT then I'm not interested, 6.5 grendel really does pull ahead from the 223 cats, still supersonic past 800yds with more retained energy.

[Tackleberry41]

Was talking to a friend yesterday, he loves ARs, builds them. As said its that 223 case, you can use a heavier bullet but just cant get anymore energy out of it than just using 55gr stuff. You need to step up to the larger cases like the 6.8 or 6.5. I looked at it, but it was a whole lot of effort for no gain. 223 is pretty easy to find, 6x45 thats pretty much handloads only. I case form for the 577/450, lots of work, but 50 cases in that is alot. A semi auto would eat em up, and you would take the time to try and find every one of them at the range.

Now if 6x45 or 25x45 was off the shelf might be onto something.

[GabbyM]

Everything in shooting isn’t about power, however. That poor much criticized 223 case may not be voluptuous but I went and bought a 222 Rem bolt gun to get an even smaller case and of course the long neck. I also like shooting it way more than I’d imagined.

[dragon813gt]

Everything in shooting isn’t about power, however.

Very true. To many people get hung up on ballistics tables. Hard to believe and game fell to a bullet before the uber magnums came out ;)

[RoyEllis]

....Now if 6x45 or 25x45 was off the shelf might be onto something.

Sharps Rifle Co. has 25x45 uppers, barrels & ammo out now, I've been thinking about a barrel but all SRC's barrels have polygon rifling....not sure they could shoot cast well (if at all) is what's holding me back from getting one to play with. An 87gr bullet @ 3000fps is fairly respectable from it.

[GabbyM]

Didn't see a pressure listed in there data. Wondering if they run up to the 5.56 NATO 62K psi?

For a cast bullet shooter. I like the looks of a 6mm x 222 with a 1:14" twist barrel. One reason is I already have three 6mm bullet molds. 1:13" may shoot the Saeco 87 grain #243 bullet better. Have the NOE 80 grain Egan and a Lyman 84 grain Loverine round nose also.

25 caliber does have a lot going for it if a person is looking to hunt game as large as deer or hogs. Just a small edge over an 80 grain Speer in 6mm. But then the 6mm is just a small bump up from the 22.

For cast bullet ease in an AR platform. 14" twist 223 Rem chamber barrel. No extra die sets to buy. 2,400 fps with a 55 grain bullet. The fifteen pound critters I've shot with my 222 Rem with cast. Sure didn't look like I needed more gun. Plenty of options.

[madsenshooter]

Gabby, NOE just came out with a heavier 6mm bullet. I had a lot of fun with my Obermeyer barreled 6x45 AR. I often thought, when I was working with it, that a bit more neck would have been nice. I should have had it chambered for the 222/6mm.

[GabbyM]

Gabby, NOE just came out with a heavier 6mm bullet. I had a lot of fun with my Obermeyer barreled 6x45 AR. I often thought, when I was working with it, that a bit more neck would have been nice. I should have had it chambered for the 222/6mm.

I saw that. It's sweet but I just can't justify buying every boolit mold out in the wild. Especially since I already have three 6mm molds. Haven't even cast any from the NOE Egan 80 grain yet. Also have the matching Egan mold in 55gr 22 caliber. Plus three new rifles in the last two years. I simply have more toys now than time to wring them all out. Life is tough.

[GabbyM]

What the 6mm x 222 case would give you in an AR platform. Is ability to run slower burning powders. H4895 comes to mind and would be a high volume load density under a 75 to 80 grain bullet at 2300 to 2400 fps in a 14 twist barrel. I bought a jug of AR-Comp which is in burn rate of H-4895 and Varget. It's reformulated RL-15. Burns faster and has temp sensitivity coatings. Have some loaded under 65gr Sierra Game Kings but haven't popped any off to get the test done. Load is near full up to the neck. I'll be trying some later this summer with cast in my 222 and 223 in the 12 twist SP-1. 14.5 grains of 4198 shoots good in my 223 AR's but barely works the action.

I have everything here, upper receiver, sights and bolt group, to build an AR upper sans the barrel. Then I have a new lower with a 1.2 lb Geisel trigger in it. Plus I discovered a $9 brass catcher bag that actually seams to work. A group buy for a 6mm x 222 1:14" twist would be very hard to pass by. It would only do two things a J bullet 223 couldn't do better. Would shoot cast boolits very well and very fast. Would be a super max night hunter for dense populated areas. Having lower muzzle flash and report. Illinois is also now bouncing the idea of allowing cans to suppress noise. I shot a 5.56mm AR-15 with a can out in AZ last fall. Was a small can but still just a little worse than a 22 RF. In Illinois there is a 300 yard minimum away from a home to discharge a firearm when hunting. At night hunting yotes that legal 300 yards can about knock a man out of his bed if you crack off a full house 54,000 psi J load from a 223. I'm on the other end of those shots now and then as I have rowdy Amish neighbors. Given the same size case. A 6mm or better a 25 caliber bore. Will have lower pressure and report from any given psi load over a 22 bore. Due to the greater expansion volume of the bore and lower muzzle pressure.

With the 14" twist bores maximized for cast. To cross over to jacketed. You couldn't' shoot any big game bullets in the 6mm as the 80 grain Speer probably would not stabilize. With a 25 you could shoot the light bullets made for the old 14 twist Savage 250-3000. But seriously. If I wanted a big game AR I'd build a 458 SOCOM and shoot my 420 grain FN.


My opinion and experience with at least 22 and 6mm is. If you want to shoot cast. Run a 14 twist barrel in 22, 6mm and 25. Then live with the weight limits or move up in caliber.

[Jupiter7]

Sharps Rifle Co. has 25x45 uppers, barrels & ammo out now, I've been thinking about a barrel but all SRC's barrels have polygon rifling....not sure they could shoot cast well (if at all) is what's holding me back from getting one to play with. An 87gr bullet @ 3000fps is fairly respectable from it.

I believe that's from a 20"+ barrel. The 25x45 sharps is almost solely based around that 87grn Speer Hot Core bullet. The gentleman selling 25-223(25x43) barrels on ar15.com has a SpecII chamber that will allow loading of 100grn bullets in the 2600fps(16" barrel)range, that gets the BC high enough to get close to my 75grn .223 loads where the hold-overs are near identical and retained energy is higher. I'm in talks with him now to get a barrel. This gun will not see cast, just can't get enough weight in the case to make it a viable cast shooter/hunter, for me. The 300blk is about the perfect marriage for cast in an AR15.

[427smith]

if your a reloader and want a 6x45 get it. got my barrel on last mon. got the dies last wed. and been playing with it last couple days. makes a great companion to my 300 blkout. No special mags or bolts to buy, dies are easy to get and making the brass is made by running 223 brass thru a 6x45 full length sizing die. that's it. So far, ar 15 cycling does not seem to be quite as picky about powder types and charges as my 300. I've still got plenty of work ( I mean fun) to do

[303Guy]

josh82, how does that '9x223' perform? It looks interesting!