6x45 / 6mm-223 12.5" short barrel

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sethperry

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I have been looking through the fourms trying to get more information on Short barrel 6x45... anyone running AR15 12.5"? I'm wanting to run 55-65 grain looking at different powders an run it moderately hard (not worried about brass) an get some velocity back... getting a thermal soon (still trying to decide) 300 yards would be about the farthest shot im thinking.. I see some load data links but when I click on them its something completely different... i was also looking at the 6mm max an that velocity with a short barrel is impressive but I have a ton of 223 brass so I would like to stick with 6x45... I'll share the 6max barrel length an specs graph i found.. But if you have any 12" data with bullet weights velocity with powders used im all ears!
Mainly used for Coyotes and coon don't care about the fur its not worth anything around me anymore..
TIA
 

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Even our good Sandhills coyotes are basically worthless except for the very very best ones, or so I've been told. I haven't bothered to pick any up in a couple years.

Anyway, I'd run with that 14" data, it wouldn't be far off I don't think. H322 would be what I'd try as I have quite a bit of it. IMO 300 yds would be a stretch for that round at night but it depends alot on what thermal you're running. That's the edge for me running a 243 and super hogster but a good 640 would stretch that significantly. I think the 6x45 is a solid choice for night hunting moderate ranges.
 
Speaking in general term, the best powders in a longer barrel are still preferred in shorter ones. One example was in my 30" 6.5-284, H-4831 was the powder of choice with 140's in the long barrel, and was the best in an 18" as well with the same bullets.

On the flip side, when I built my 18" 22x47 Lapua, I needed to go a little faster in burn rate, from H-4350 with 80 grain bullets, to H-4895 for the 52's.

Another general rule of thumb is around 25 FPS gain/loss per inch of barrel length.
 
204 AR said:
Even our good Sandhills coyotes are basically worthless except for the very very best ones, or so I've been told. I haven't bothered to pick any up in a couple years.

Anyway, I'd run with that 14" data, it wouldn't be far off I don't think. H322 would be what I'd try as I have quite a bit of it. IMO 300 yds would be a stretch for that round at night but it depends alot on what thermal you're running. That's the edge for me running a 243 and super hogster but a good 640 would stretch that significantly. I think the 6x45 is a solid choice for night hunting moderate ranges.
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I'm in NE ia my dad has been trapping them an the most he has gotten for the nice ones has been 5$... its crazy times... I don't think he is going to waste his time selling them anymore...

The one I have been looking at is the rattler 35ts 35 640... rix has a thermal that looks more like a traditional scope that i have been looking at also.. it has digital zoom but it has another type of zoom function that doesn't distort the picture..

The 6x45 seems super impressive for what it is... from everything I've been seeing u can get a higher velocity than 223 running the same weight of bullet.. im sure you loose BC but out to 300 im not sure that is a big deal?
 
alf said:
Speaking in general term, the best powders in a longer barrel are still preferred in shorter ones. One example was in my 30" 6.5-284, H-4831 was the powder of choice with 140's in the long barrel, and was the best in an 18" as well with the same bullets.

On the flip side, when I built my 18" 22x47 Lapua, I needed to go a little faster in burn rate, from H-4350 with 80 grain bullets, to H-4895 for the 52's.

Another general rule of thumb is around 25 FPS gain/loss per inch of barrel length.
Click to expand...
That is interesting.. I always thought the shorter barrel you would want different/faster powder.. makes sense though! Thank you!
 
If you're looking to play with calibers/ loads/ barrel length etc.. a program like Quickload is well worth the investment. Plug numbers in and see the results. It won't be 100% of course, but it will get you in the ballpark without wasting expensive resources.
 
Bob Azadi said:
If you're looking to play with calibers/ loads/ barrel length etc.. a program like Quickload is well worth the investment. Plug numbers in and see the results. It won't be 100% of course, but it will get you in the ballpark without wasting expensive resources.
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Sounds good! I will take a look at that... Thank you for your help!
 
varminter .223 said:
Aa2200 is the fastest I've seen in the 16" version. I assume it would still be fast in a bit shorter barrel.
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That is what I have been seeing.... or H322 I believe... I have also been looking more at the 6mm max that thing is pushing close to 3200 fps with a 12.5" barrel.... pretty impressive
 
Personally, I'd just go with a 16" barrel, get the free velocity over a 12.5", and skip the hassle & $200 cost of the tax stamp of a SBR.
 
alf said:
Personally, I'd just go with a 16" barrel, get the free velocity over a 12.5", and skip the hassle & $200 cost of the tax stamp of a SBR.
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I don't disagree with that advice at all... i have just had alot of different AR barrel lengths from
8" -24" but that 12" barrel is just what I always grab... its not to short but not too long.. my 16" just sits in the safe anymore... especially when you slap a can on it..
 
I went with. 14.5” barrel. I’m gonna run the 68-75gr stuff. Same idea for max distance. But I’ll play with it too. I’ve got some h4198 and n133. Those will be the first ones I try. I formed up 100pcs of brass yesterday. Bullets will be here tomorrow. Then just waiting on the barrel
 
nastynatesfish said:
I went with. 14.5” barrel. I’m gonna run the 68-75gr stuff. Same idea for max distance. But I’ll play with it too. I’ve got some h4198 and n133. Those will be the first ones I try. I formed up 100pcs of brass yesterday. Bullets will be here tomorrow. Then just waiting on the barrel
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I ended up going with the 6max.. I still might grab a 6x45 barrel sometime though.. its pretty impressive for what it is...
 
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