6x45 (6mm-.223) build thread

[Rob0115 1,105]

Well, what supposed to be a Black Friday Grendel turned into a Black Friday wildcat 6x45 AR. The 6x45 takes 5.56 brass and expands the neck to 6mm to allow for larger projectiles. I have no particular use for this rifle but will nonetheless enjoy shooting it. The real intent was to get a cheap rifle from quality parts on sale for Black Friday. I had a few odds and ends so they aren't in the cost.

 

Here's what I ordered:

Spikes forged upper receiver $101

PSA premium BCG 78.49

BLackhole barrel 239

Giseele gas block 27.30

ALG LPK w/QMS 65.10

ALG 15" M-lok v1 101

ALG tru-milspec buffer tube kit (buffer and spring) 53.60

 

I have a magpul moe stock, a Spikes lower, gas tube and pin, bcm charging handle. I also have the barrel nut wrench for the m-LOk but bought a spare for 3.50 on sale.

 

ALG has a disclaimer that it'll be 2-3 weeks for delivery.

 

I wish this was all I bought but I bought a bunch of shit for my two AKs that I'm building. Damn I hope my wife doesn't read this.

 

Oh, well this should provide me hours of fun. I'll make some test rounds this week while waiting for the stuff.

[Rob0115 1,105]

Assembled the upper with BHW barrel. I didn't pin the Geiselle gas block because I didn't want to drill the barrel. It's a plinking rifle, if I like it I'll drill and pin the block to the barrel. I need to install the LPK and it's done. I made 5 each test rounds with 87 grain and 100 6mm bullets.

 

The ALG rail is super nice especially for 100 bucks. I wish I had bought another.

 

I started my 16" Grendel using stuff I had, faxon barrel, but just transferring it to AA Grendel marked upper and lower. It looks petty good too.

 

I just started looking at al the AR calibers i have and it's probably to many but WTF who cares?

 

5.56, 6x45, 6mmAR, 6.5 Grendel, 6.8 SPC II, 300 AAC, .458 Socom.

[OfcrFek 21]

Post some pix once its completed. Curious about this one. What round is it should it be ballistic-ly similar to??

[Rob0115 1,105]

I don't know what it would be ballisticslly similar to as far as another cartridge. What it does provide is a larger projectile at higher velocities out of the same platform. It also provides better BC and wide bullet choice, not that the latter is an issue with .223.

 

Here's the wiki article.

 

https://en.m.wikipedia.org/wiki/6×45mm

 

Ballistic chart showing energy gains over 5.56, 300 AAC and 7.62x39

http://www.ammoland.com/wp-content/uploads/2015/06/6.8x45mm-Urban-Combat-Cartridge-UCC-Ballistics-Chart.jpg?10cd65

[Old School 611]

I don't know what it would be ballisticslly similar to as far as another cartridge. What it does provide is a larger projectile at higher velocities out of the same platform. It also provides better BC and wide bullet choice, not that the latter is an issue with .223.

 

Here's the wiki article.

 

https://en.m.wikipedia.org/wiki/6×45mm

 

Ballistic chart showing energy gains over 5.56, 300 AAC and 7.62x39

http://www.ammoland.com/wp-content/uploads/2015/06/6.8x45mm-Urban-Combat-Cartridge-UCC-Ballistics-Chart.jpg?10cd65

Rob - I always thought the 6mm-223 was down on case capacity but apparently they're getting good velocity.

Let me know.   Very interesting.

[Rob0115 1,105]

Rob - I always thought the 6mm-223 was down on case capacity but apparently they're getting good velocity.

Let me know.   Very interesting.

 

I definitely will.   I don't really have a use for this other than curiosity and boredom taking over.  I won't compare with 6mmAR over distances but it's interesting how well it does given the constraints of just necking up a 5.56 cartridge.  

[Rob0115 1,105]

OK--Grendel and 6mm-.223 are assembled.  If I can I'm going to test fire at least the 6x45 because I made some ammo for it.  I didn't have the to assemble any grendel rounds.  Oh, well.  

[Rob0115 1,105]

Wow the 6x45 shoots not loud, super soft shooting and accurate. Only shot 50 yards in doors with an aim point. Pics later. I'll put a scope on it to see how accurate it is.

[Bully 749]

Curious to see how this does, accuracy wise.  It's for sure something I'd be interested in.  I like the use of the 223 brass, for sure.  Save me a lot of loot as I'm starting a 6.5G build but could be convinced to switch it up.  I'm looking for a 300yd fun semi auto.  This could work.

 

Are you single loading or shooting from a mag?

[Rob0115 1,105]

Curious to see how this does, accuracy wise.  It's for sure something I'd be interested in.  I like the use of the 223 brass, for sure.  Save me a lot of loot as I'm starting a 6.5G build but could be convinced to switch it up.  I'm looking for a 300yd fun semi auto.  This could work.

 

Are you single loading or shooting from a mag?

 

The first round I single loaded because I only had long A-Max bullets that I use in my 6mmAR.  I have some SMKs that I'm going to fire from the mag.  I just got an optic for it so I took the RDS off.  From what I have read it's pretty accurate out to a few hundred yards but the proof is in the pudding.  I'm going to mount a 1-6x given I'll mostly shoot 300 and in on it.  

 

The use of .223 brass is why I ended up doing it.  It's like building a standard AR, bolt and all, but changing the barrel like a 300 BO. No cutting and no fire forming on the brass is needed, just stretch it out.  

 

I was going to build this instead of the grendel but like an ass ended up doing both.  Sometimes I can't be left alone.  

[Bully 749]

Yeah, after a bit more snooping around I think I'm gonna just go straight 6.5Grendel. I think it will fit what I'm looking for a bit better.

 

Be sure to post your targets.

[Rob0115 1,105]

If it were choosing one it would be a Grendel. However, i would choose my 6mmAR over the Grendel for precision shooting from an AR. The problem is only a few people have the reamer. My barely came from barrel man in Texas and was reamed and assembled by Youngs gunsmithing in Montana. They were very inexpensive for the quality of the work. However if you're in a hurry it's a no go. It'll take a couple months to get it back.

 

Btw, just to keep my good name in tact, Frank made me build the 6mmAR. I don't want everyone to think I don't have any enablers around. . He was right though it is the best shooting round I've ever had out of an AR Platform.

[Bully 749]

Frank is a very good friend that I hate.

[SuRrEaLNJ 294]

first iive seen of the 6x45. color me super intrigued. 

 

not to steal your thread, but since you own so many ar calibers can you be more specific on how the 6x45, 6mmAR, 6.5 Grendel, 6.8 SPC II and 300 AAC compare? 

[Rob0115 1,105]

Let's take a shot at it, no pun intended. 6mmAR is my version of a precision rifle in an AR platform. It is the most accurate cartridge I've ever fired from an AR over long ranges. It isn't highly charged and should have really good barrel life. There's an enormous selection of bullets for match shooting, hunting too but I don't with this, in various weights. It's also very forgiving on powder types. The load data is available for h4895, XBR8208, CFE223, N140 and a few more.

 

300 AAC I've dissesembled, gotten a tax stamp and SBR'd it with a suppressor. It's a great heavy subsonic round that is heading safe suppressed. I may hog hunt with it. There's a lot of bullet weights, I mostly use H110 or Lil' Gun powder. I've had it for a while just for the novelty but until I moved the rifle to Florida and transformed it I really didn't see any value in it.

 

6.5 Grendel is a really good powerhouse. It's not as BC as 6mmAR that was born from the cartridge but for long distance, short distance or hunting it's great heavy bullet AR. The amount of choices on bullets, shapes and weights, powders, etc is quite extensive. There is big community support and a lot of folks hunt with the round and precision shoot.

 

6.8 SPC II, I have regrets on this one. I'm not sure what to do with it. I built it from 100% Wilson combat components and it's a bit disappointing. Not extremely great at distance, brass is as much or more this new lapua Grendel brass. There's load data and choices on components but in my opinion it's the answer to a question that no one asked. The debate rages on Grendel vs 6.8 and has gotten a bit religious but I'm completely in love with the Grendel. I've built two of them.

 

6x45 is just my love affair with wild cat rounds. It uses 5.56 brass, which is cheap and I have tons of, many 6mm bullet choices and it handles 55 to 100 grain. It's a good caliber at intermediate ranges and it's built from 100% 5.56 components except for the barrel. I bought the barrel for cheap on a BHW Black Friday sale and bought some dies. I've test fired it and was very soft shooting and accurate at 50 yards with an unmagnified RDS. I put a 1-6 on it and will go to cherry ridge to see how it does at 2-300 yards. According to the data that's the sweet spot for the round. Components are cheap for loading it, there is factory ammo. The barrel life is longer than a 5.56 as well. So it's basically a 5.56 that can throw slightly heavier bullets with better BC. It's probabaly a great varmint rifle.

 

As I mentioned to Topher via text if I could only have one, thankfully that's not the case 'cause I like variety, it would be the 6mmAR. However that's going to be the priciest one and the toughest to get built. I waited for quite some time to get my upper assembled from a custom reamed barrel by Young's Gunsmithing in Montana. They did great work for a great price and a soft sweet shooter that I love to take out on the range.

 

Hope this is somewhat useful.

[Rob0115 1,105]

Yeah, after a bit more snooping around I think I'm gonna just go straight 6.5Grendel. I think it will fit what I'm looking for a bit better.

Be sure to post your targets.

Im waiting for the optic to show up by you can shoot it next week at GFH if it shows up. I'm loading some round right now. 123 grain SMK.

[SuRrEaLNJ 294]

Hope this is somewhat useful.

 

Verry actually. Again not to hijack, but the ar apeals to me almost exclusively in odd calibers. I dont have alot of 5.56 love personally

[Rob0115 1,105]

Verry actually. Again not to hijack, but the ar apeals to me almost exclusively in odd calibers. I dont have alot of 5.56 love personally

Not hijacking at all. The cheapest odd caliber to shoot would be 6x45 (6mm-.223). There's plenty of load data, there's factory (don't know the prices), uses cheap .223/5.56. The dies are priced according to most die sets. It's just a different barrel than 5.56 but same bolt.

 

I looked at 25x45 but brass shortening is required, less data, dies are special order and a couple hundred bucks and it seems to be comaparable to 6x45.