6X45 questions

[Emilio]

Does anyone here shoot the 6X45? I'm planning a build and would like a little info. I would like to shoot the 107 HPBT and would like to know what barrel length you have and what twist. If possible also. the COAL for the 6X45 using the 107ge. Thank you.

 

[cturne08]

I built an AR in 6 X 45 as a predator rifle last year and love it. I'm restricted to around the 80 gr. range in a hollow point bullet because of the magazine COAL issue. I have a hard time with tipped bullets (v-max) and COAL when I get above 80-ish grains - mag length is 2.260. I'm guessing that you are thinking about building a bolt gun so not sure if this helps.

*Shilen select 26" 1-8 twist.

 

[redneckbmxer24]

I haven't finished my 6x45 yet but I did a few mock up rounds and it has made me a bit leery. At any sort of 223 mag length be it AR's or a bolt gun mag the heavy bullets are going to be seated way deep, with the 107 probably below the bearing surface. With the 95gr Berger classic hunter I seated at AR mag length the bearing surface is only .015" above the case neck at trim to length. The bullet is seated so deep I'm considering starting bullets right side up and fully seating them in a press mounted upside down so that I can actually get some powder in them without crunching. Even then I think I'm only looking at 2400-2500fps if I'm lucky.

I'm thinking the 6x45 is probably more ideal for lighter bullets at mag length or heavier bullets if single fed. All the numbers I've ran for 6x45 loads show a standard 223 load with 77gr owning it at mag length. The bolt gun loads I've ran the numbers on for the 6x45 my 223AI with 75 AMAX laughs at.

If it wasn't for the fact I want a AR that's hunting legal and I already have all kinds of 223 brass, powder, primers, and 6mm bullets then I would have never entertained it.

 

[Emilio]

I was planning on building it on bolt and feeding through AI mags.

 

[buffybuster]

I was planning on building it on bolt and feeding through AI mags.

I have two 6x45's, one with a 20" and 24" barrel. I also shoot 107's. I get 2560-2620fps which tracks the same as a .308Win with 175's. I use the .223rem AICS mags 2.5" OAL. Most appropriate .308win powders work well.

8-twist on the barrels and they shoot bug holes. No recoil. Brass is fire and forget as I have buckets of 5.56.

 

[my human host]

I haven't finished my 6x45 yet but I did a few mock up rounds and it has made me a bit leery. At any sort of 223 mag length be it AR's or a bolt gun mag the heavy bullets are going to be seated way deep, with the 107 probably below the bearing surface. With the 95gr Berger classic hunter I seated at AR mag length the bearing surface is only .015" above the case neck at trim to length. The bullet is seated so deep I'm considering starting bullets right side up and fully seating them in a press mounted upside down so that I can actually get some powder in them without crunching. Even then I think I'm only looking at 2400-2500fps if I'm lucky.

I'm thinking the 6x45 is probably more ideal for lighter bullets at mag length or heavier bullets if single fed. All the numbers I've ran for 6x45 loads show a standard 223 load with 77gr owning it at mag length. The bolt gun loads I've ran the numbers on for the 6x45 my 223AI with 75 AMAX laughs at.

If it wasn't for the fact I want a AR that's hunting legal and I already have all kinds of 223 brass, powder, primers, and 6mm bullets then I would have never entertained it.

It is possible to modify the follower to make a 223 based case run in a 308 mag box for a SA 700. Not sure if that's what you're considering, but it can be done. I made up a couple of them for an old duffer who likes the 222 Rem Mag.

 

[redneckbmxer24]

I've got an AR barrel so I'm limited to AR mags. I'm about ready to just scrap the whole thing.

 

[BoilerUP]

I have two 6x45's, one with a 20" and 24" barrel. I also shoot 107's. I get 2560-2620fps which tracks the same as a .308Win with 175's.

2560fps with 107s from the 20"?

Care to share load data?

 

[buffybuster]

2560fps with 107s from the 20"?

Care to share load data?

I have used Benchmark, Xterminator, TAC, IMR4320, 4895, etc. All have given that velocity somewhere around 23.5-25grs.

 

[redneckbmxer24]

How are you getting that much powder behind it?

 

[BoilerUP]

How are you getting that much powder behind it?

Bolt gun at 223 AICS mag OAL, vs. AR mag OAL?

 

[knockemdown]

Agree with above.
The 6x45 shines with light-mid weight bullets, which run very efficiently from a short barrel.
A 55gr N-Btip near 3K from a 16" tube on 25gr of powder will make ya smile. IMHO, leave the heavy bullets to something with more case capacity...