AR10 caliber

[Samson]

If you put the 270AR barrel and dies on 68forums I bet you would sell it faster than you think. H developed both the 270AR/MSR to fit in a 2.26 oal platform. Why hamstring yourself in a bolt gun when you can get more case capacity with a different calliber? In a gas gun its much better than anything the grendel can do.

[Gunnyart]

8.6blk ?

[RifleBowPistol]

I shoot 22cm in a bolt gun and 6.5cm in an Aero M5. The 22cm is shorter, and my load will fit in AR10 mag using the 88gr ELD-Ms. Oal is at 2.74 and that bullet touches the lands at 2.79 in my gun. Its a fun round, not much umph past 600. Its hard to hear it hit steel at 1k. I also have a 270 MSR in an Aero M4 shooting 140 classic hunters and leverrevolution. Its probably my fav right now, but to answer your question though, yes 22cm will fit in an ar10 no problem. We've killed some pigs and Aoudad with the 22cm too.

Just curious, what velocities are you getting from the 22 CM and what barrel length?



I am going to bet that 270 MSR is one of the rounds Bruce Finnegan came up with. He has cooked up a lot of AR15 and AR10 wildcats. I have not been on the groups, that Bruce and some others are on, in years. Multiple people decided the 270 AR was not the best idea for a AR15, for the same reasons, I concluded. I know Bruce has since designed a bunch of AR15 calibers with a shorter case, in about every bore size from 22, up to 30 caliber. He did the
same with wildcat calibers based off of the 270AR, that Harrison came up with.

Bruce has designed a bunch of AR15 calibers and AR10 calibers, in a wide range of bore diameters, that have large diameter cases, to get a decent powder charge, but then he shortened the cases so you can load the longer, higher BC designed bullets, or heavier bullets in he chamberings, and still fit in either a AR15 or a AR10 mag, depending on which caliber.

I will try to remember to ask him about the 270 MSR, I would bet that's one of his.

[Samson]

Just curious, what velocities are you getting from the 22 CM and what barrel length?



I am going to bet that 270 MSR is one of the rounds Bruce Finnegan came up with. He has cooked up a lot of AR15 and AR10 wildcats. I have not been on the groups, that Bruce and some others are on, in years. Multiple people decided the 270 AR was not the best idea for a AR15, for the same reasons, I concluded. I know Bruce has since designed a bunch of AR15 calibers with a shorter case, in about every bore size from 22, up to 30 caliber. He did the
same with wildcat calibers based off of the 270AR, that Harrison came up with.

Bruce has designed a bunch of AR15 calibers and AR10 calibers, in a wide range of bore diameters, that have large diameter cases, to get a decent powder charge, but then he shortened the cases so you can load the longer, higher BC designed bullets, or heavier bullets in he chamberings, and still fit in either a AR15 or a AR10 mag, depending on which caliber.

I will try to remember to ask him about the 270 MSR, I would bet that's one of his.

Harrison did the MSR as well, after he realized it should be easier to make brass. The MSR you just run a 6 dasher case through the resizing die and youre done. No trimming, no neck turning. Thats probably what killed the 270 AR and why he never made any more of those barrels. For the 22cm im seeing 2780fps on a 19.1" barrel with the 88gr eld-m

[RifleBowPistol]

If you put the 270AR barrel and dies on 68forums I bet you would sell it faster than you think. H developed both the 270AR/MSR to fit in a 2.26 oal platform. Why hamstring yourself in a bolt gun when you can get more case capacity with a different calliber? In a gas gun its much better than anything the grendel can do.

I would have guessed Bruce designed the 270 MSR, if not Bruce, Harrison would be the other guy who would likely have done so. So Harrison has a thing for the 270 caliber? I have been trying to understand his logic on choosing the .277 bore size for the caliber he called the 270AR. I would have gone with a 6.5mm bore. But then it would have been even closer to being a 6.5 Lapua, that he based the 270 AR on.

My thinking on his creation of the 270AR, was he saw the potential of the 6.5 Lapua, but could not put his name on it. So he changed it around a bit, without noticeably changing the performance capability of the round. Then he could call it his.

The 270AR is a pretty nice round, but definitely limited to only using shorter bullets to get those good velocities, and be able to fit in the AR15 mags. It's definitely more powerful than a 6.5 Grendel, but being limited on what bullets that can be run, is kind of irritating. Knowing what all I know now, about the round, even if I could just order a barrel easily and get dies and brass easily. I would not buy one, at least not a AR15 in that caliber. Some other gun with a longer receiver and mags or mag well, possibly, but not a AR15.

If you chamber a gun with a longer magazine/ longer receiver, you would definitely increase the potential of the caliber. You sound like Harrison. I can build a much lighter rifle out of a bolt gun, than an AR, definitely when you compare a short action, 700 action to a AR10. Chambering a very light short action rifle for either a 6.5 Lapua, or the 270 AR, with a 24" barrel, would make for a very nice, light deer gun. When done the way I am thinking of going, it will be much lighter than a AR10.

If I could unload the 270 AR barrel, dies and brass, for a reasonable price, they would definitely be gone. Then I would have a 6.5 Lapua built.

[RifleBowPistol]

Harrison did the MSR as well, after he realized it should be easier to make brass. The MSR you just run a 6 dasher case through the resizing die and youre done. No trimming, no neck turning. Thats probably what killed the 270 AR and why he never made any more of those barrels. For the 22cm im seeing 2780fps on a 19.1" barrel with the 88gr eld-m

From what I was told about the 270AR, he created the round to try and win the competition for the new US military battle rifle caliber. From what I heard, the caliber did pretty good, out lasted other rounds that were also competing to be the new US battle rifle caliber. But once his round was out of the running, he dumped it. But at the same time, guys who had bought barrels and were loading the round, found the problem with the overall length of the round being too long to make use of a lot of different bullets, and then even with the Sierra 130 gr Game King, you could not seat it any farther out of the case, or it would not fit in the mags.

I bought my barrel, right after what turned out to be the last group buy on 270AR barrels. I almost got in on the barrel group buy, but the only barrels that were an option to buy, on that group buy, I did not like. So I contacted Harrison, and asked him about a barrel. He sold me what I wanted, but said that barrel was not built to sell, it was his pressure test barrel. It is not labeled in any way, no caliber identification, no brand. Then he told me to contact Whidden Gun Works for the dies. When I contacted him, he said they had not made any of those dies in a while. But he found one last set, and sold them to me.

Then probably eight months to a year later, I contacted Harrison, about the idea of reaming a barrel for me, he would not even talk to me about the caliber. He told me he was not doing anything with the caliber anymore.

[Samson]

I would have guessed Bruce designed the 270 MSR, if not Bruce, Harrison would be the other guy who would likely have done so. So Harrison has a thing for the 270 caliber? I have been trying to understand his logic on choosing the .277 bore size for the caliber he called the 270AR. I would have gone with a 6.5mm bore. But then it would have been even closer to being a 6.5 Lapua, that he based the 270 AR on.

My thinking on his creation of the 270AR, was he saw the potential of the 6.5 Lapua, but could not put his name on it. So he changed it around a bit, without noticeably changing the performance capability of the round. Then he could call it his.

The 270AR is a pretty nice round, but definitely limited to only using shorter bullets to get those good velocities, and be able to fit in the AR15 mags. It's definitely more powerful than a 6.5 Grendel, but being limited on what bullets that can be run, is kind of irritating. Knowing what all I know now, about the round, even if I could just order a barrel easily and get dies and brass easily. I would not buy one, at least not a AR15 in that caliber. Some other gun with a longer receiver and mags or mag well, possibly, but not a AR15.

If you chamber a gun with a longer magazine/ longer receiver, you would definitely increase the potential of the caliber. You sound like Harrison. I can build a much lighter rifle out of a bolt gun, than an AR, definitely when you compare a short action, 700 action to a AR10. Chambering a very light short action rifle for either a 6.5 Lapua, or the 270 AR, with a 24" barrel, would make for a very nice, light deer gun. When done the way I am thinking of going, it will be much lighter than a AR10.

If I could unload the 270 AR barrel, dies and brass, for a reasonable price, they would definitely be gone. Then I would have a 6.5 Lapua built.

Straight out of the horses mouth :

I know there will be a bunch of guys with a 6.5 fetish yakking "why not a 6.5". If I shorten the case enough to use the long 6.5 bullets it's back to the length of a 6.5BRX. The 6.5 BRX has almost the same case capacity as a 30RAR necked down to 6.5 and the BR brass is much easier to find. The BC doesn't kill animals. This is about making the best AR15 cartridge for hunting not punching paper.



So there you go, developed for hunting, not punching paper. He had developed his BRX line to get a little more performance out of BR line and call it his own for the paper punchers. Not the case with the 270AR/MSR. 68forums has the history of all his cartridges if youre interested, go do some reading. H was VERY upfront in the orginal announcement thread that the 270AR would not work with anything over 150gr.

Personally I think he made it cause he was bored and to **** off the 6.5 fanbois. He made it a habbit to do that over the years and got him banned from some forums.

[RifleBowPistol]

Straight out of the horses mouth :

I know there will be a bunch of guys with a 6.5 fetish yakking "why not a 6.5". If I shorten the case enough to use the long 6.5 bullets it's back to the length of a 6.5BRX. The 6.5 BRX has almost the same case capacity as a 30RAR necked down to 6.5 and the BR brass is much easier to find. The BC doesn't kill animals. This is about making the best AR15 cartridge for hunting not punching paper.



So there you go, developed for hunting, not punching paper. He had developed his BRX line to get a little more performance out of BR line and call it his own for the paper punchers. Not the case with the 270AR/MSR. 68forums has the history of all his cartridges if youre interested, go do some reading. H was VERY upfront in the orginal announcement thread that the 270AR would not work with anything over 150gr.

Personally I think he made it cause he was bored and to **** off the 6.5 fanbois. He made it a habbit to do that over the years and got him banned from some forums.

When you loose velocity quicker, you loose energy quicker, you increase bullet drop, you increase time of flight. If you don't loose near as much velocity down range, and the bullet is of a good designed hunting bullet. The one with the higher BC will give you improved long range performance, as in will do more damage. When you are starting off with a small caliber to begin with, you are going to be limited to shorter ranges or you find a bullet with higher BC numbers to stretch out the range a bit further.
It has nothing to do with punching paper, paper don't care what velocity or how much energy you hit it with. If you are shooting paper, you know the range, and can easily dial in the bullet drop. So it would not matter much, if you had 25" of bullet drop or 250" of drop, at whatever range. The only advantages of a high BC bullet when shooting paper, would be less bullet drop and shorter time of flight. Anytime you can reduce time of flight, you are going to increase your overall accuracy at longer ranges, less problem with wind drift. When hunting in different conditions, the wind, will almost always be a factor.

Harrison created the 270AR, then he killed it by completely dropping it, it was not a case of nobody wanted to buy 270AR barrels anymore. He killed it, he stopped making the barrels. He knew it had flaws. Then I am getting told he designed the 270 MSR, what is it, a shorter case round, that allows you to use longer bullets, higher BC bullets.

[RifleBowPistol]

I finally got some time to do some reading on the 22 Creedmoor. It seems to be what I suspected it would be. I am pretty sure, that is a round I want to try out. I think it should work well in a AR10. At some point, I want to try out a 6mm, possibly a 6mm Creedmoor, possibly a 6X47 Lapua, maybe the old 6mm BR. I think I want to try out a round that will shoot some heavy 22 caliber bullets first, once I have got some experience with those, I would like to try a 6mm, something. At some point, I will look into what is out there in 6mm, if I did a 6mm, I would want it to push 100+ grain bullets, to 3500+ fps. Maybe something like a 284 Win. necked down to 6mm. I looked up data for a 6mm-284, it looks like they are good for about 3200 with a 100 gr. bullet. Then found a 6mm PRC, that is supposed to be good for around 3350, to 3400 fps, with 100 gr. bullets. That will probably be the 6mm I try out some day.