single cartridge for multiple "assault rifles" your choice?
- Thread starter jason41987
- Start date
- Status
jason41987
member
- Joined
- Apr 10, 2012
- Messages
- 1,293
heres just some of the thoughts ive been working on...
7.62x39 is out of the question, doesnt work in anything with a magwell it seems, and the BC is too low for distance, so toss that one aside.. same goes for .300 aac blackout
my choices seem to be 6mm AR, 6.5mm grendel, and 6.8mm SPC.. 6mm AR is just a 6.5mm grendel necked down to a bullet with less selection in projectiles, so toss that one out
(geeze, i just feel a 6.8 vs 6.5 debate coming.. but ill stay unobjective)
6.8mm SPC is easier to find people able to chamber barrel blanks for, 6.5mm only recently became saami approved after alexander arms released their hold on it so not much has become available for this so far
.270" barrel blanks dont offer much selection, 6.5mm barrel blanks can be found in many twist rates and groove patterns, and theres a larger supply of bullets
6.8mm SPC is easier to machine a 5.56mm bolt out to because of its smaller rim diameter, and 6.5mm grendel works with pre-existing 7.62x39mm bolts
-----
rifles to convert, some are 5.56mm chambered, some are 7.62x39 chambered, its easier to convert a 5.56mm to 6.8mm SPC, easier to convert a 7.62x39mm rifle to 6.5 grendel... most if not all of the 5.56mm rifles do offer 7.62x39mm parts (ar15s, sig rifle, and nearly any new modular rifle).. not all 7.62x39mm rifles offer many parts or resources to convert to 5.56mm (to machnie a 5.56mm bolt up to 6.8 for an SPC conversion).. these include rifles like the SKS, VZ58 which are 7.62x39mm only
----
conclusion.. if i go with 6.5mm, to convert all rifles i will either have to machine a pre-existing bolt face up to .44", or not need to machine the bolt face at all... for 6.8mm, all 5.56mm bolt faces would have to be machined up, but most 7.62x39mm rifles will require an entirely new bolt... the 6.5mm might be the better all-around package for converting multiple rifles of different calibers
---
i must ask one question though... can 6.5mm grendel brass actually be made from 7.62x39mm brass?.. and people say it performs best in 18"+ barrels... is this due to using a slower burning powder, correctable with hand loads or is there something else about the design?
7.62x39 is out of the question, doesnt work in anything with a magwell it seems, and the BC is too low for distance, so toss that one aside.. same goes for .300 aac blackout
my choices seem to be 6mm AR, 6.5mm grendel, and 6.8mm SPC.. 6mm AR is just a 6.5mm grendel necked down to a bullet with less selection in projectiles, so toss that one out
(geeze, i just feel a 6.8 vs 6.5 debate coming.. but ill stay unobjective)
6.8mm SPC is easier to find people able to chamber barrel blanks for, 6.5mm only recently became saami approved after alexander arms released their hold on it so not much has become available for this so far
.270" barrel blanks dont offer much selection, 6.5mm barrel blanks can be found in many twist rates and groove patterns, and theres a larger supply of bullets
6.8mm SPC is easier to machine a 5.56mm bolt out to because of its smaller rim diameter, and 6.5mm grendel works with pre-existing 7.62x39mm bolts
-----
rifles to convert, some are 5.56mm chambered, some are 7.62x39 chambered, its easier to convert a 5.56mm to 6.8mm SPC, easier to convert a 7.62x39mm rifle to 6.5 grendel... most if not all of the 5.56mm rifles do offer 7.62x39mm parts (ar15s, sig rifle, and nearly any new modular rifle).. not all 7.62x39mm rifles offer many parts or resources to convert to 5.56mm (to machnie a 5.56mm bolt up to 6.8 for an SPC conversion).. these include rifles like the SKS, VZ58 which are 7.62x39mm only
----
conclusion.. if i go with 6.5mm, to convert all rifles i will either have to machine a pre-existing bolt face up to .44", or not need to machine the bolt face at all... for 6.8mm, all 5.56mm bolt faces would have to be machined up, but most 7.62x39mm rifles will require an entirely new bolt... the 6.5mm might be the better all-around package for converting multiple rifles of different calibers
---
i must ask one question though... can 6.5mm grendel brass actually be made from 7.62x39mm brass?.. and people say it performs best in 18"+ barrels... is this due to using a slower burning powder, correctable with hand loads or is there something else about the design?
jason41987
member
- Joined
- Apr 10, 2012
- Messages
- 1,293
why own multiple rifles?.. because i like collecting rifles?
TexasPatriot.308
Member
I like AR15s, but AR10s and M1As just go so much more punch and the ammo is available and reasonable. (.308 of course)
jason41987
member
- Joined
- Apr 10, 2012
- Messages
- 1,293
this is about buying a new rifle, its to convert pre-existing ones, the limitations on cartridge length and bullet diameter are the limits for a reason
jason, you asked for opinions. You're getting them. Your plan just doesn't make much sense. What I'm gathering so far is that you want a bunch of guns in the same caliber and you're looking to standardize on a caliber that's really going to be cost prohibitive, not to mention that it's going to have you hunting for ammo.
If a reason for having all of this firepower is to be prepared for the zombie apocalypse, you're going to be standing there with your dry 6.8, 6mm or whatever, while everyone else is tossing around mags of 5.56.
In any case, you should also plan to have at least a few spare bolts laying around too.
If a reason for having all of this firepower is to be prepared for the zombie apocalypse, you're going to be standing there with your dry 6.8, 6mm or whatever, while everyone else is tossing around mags of 5.56.
In any case, you should also plan to have at least a few spare bolts laying around too.
browningguy
Member
There is no cartridge for the AR15 platform suitable for shooting elk at anything over point blank range.
Now for target shooting with a factory loaded round the 6.5 Grendel appears to be the obvious choice with better down range ballistics than just about anything. With the 123 gr. Amax and Scenar loads it's pretty darn good for an AR round.
Also if you don't mind handloading look at the 6mm AR and Turbo round at http://6mmar.com/ .
Now for target shooting with a factory loaded round the 6.5 Grendel appears to be the obvious choice with better down range ballistics than just about anything. With the 123 gr. Amax and Scenar loads it's pretty darn good for an AR round.
Also if you don't mind handloading look at the 6mm AR and Turbo round at http://6mmar.com/ .
jason41987
member
- Joined
- Apr 10, 2012
- Messages
- 1,293
.30-30 has killed more elk on this planet than any other cartridge out there, and you want to tell me something ballistically superior to it in every way isnt going to do the job atleast as well, likely far better?.. i will have to disagree with that completely
also, i already mentioned why i wouldnt be too interested in 6mm AR.. its 6.5 grendel necked down to a less common bullet diameter, since reloading would be almost required it seems having a more common bullet would be better
---
and to other posters, i did ask for opinions, but i also gave criteria, larger than a .223 (so 6mm minimum) and no larger than .270, with no more than about a 2.3" overall cartridge length
Last edited:
2.260, magazine restriction. I like your idea of a 6mm something bullet, but it is not pratical in a AR-15 magazine that would give you an good selection of bullets to use (case size too small). My favorite round is the 243 and I looked into building a 243 AR, you need to start with a AR-10 rifle lower. It too was not pratical due to cost and magazine availability (different brand lowers, different mags).
I buy different socket sets for different jobs, there is no one size fits all. I am affraid that that might be the case here. (you will need more powder than a 223/5.56 case will hold.)
Jim
jason41987
member
- Joined
- Apr 10, 2012
- Messages
- 1,293
i like the ballistics of the .243 as well, very, very flat trajectory, and it maintains more energy downrange than a lot of other cartridges based on the .308...
2.3 is the length allowed for 6.8mm SPC in special 6.8mm SPC magazines for the AR.. but its true that it is a stretch in a lot of rifles that may not use these magazines for a longer COAL
ultimately though it seems 6.5mm grendel or 6.8mm SPC will be the choice... and the minor ballistic differences between these two dont really concern me, there are more important differences i need to focus on before making a decision
2.3 is the length allowed for 6.8mm SPC in special 6.8mm SPC magazines for the AR.. but its true that it is a stretch in a lot of rifles that may not use these magazines for a longer COAL
ultimately though it seems 6.5mm grendel or 6.8mm SPC will be the choice... and the minor ballistic differences between these two dont really concern me, there are more important differences i need to focus on before making a decision
jason41987
member
- Joined
- Apr 10, 2012
- Messages
- 1,293
anyway, as i said its to get current rifles to share the same cartridge... if i had the power to make them magically take a slightly longer cartridge, id probalbly base a wildcar on the 22-250 cartridge.. nothing i can do about that, if i could change the limits, they wouldnt be limits
chaser_2332
Member
- Joined
- Mar 22, 2009
- Messages
- 516
how is a 6mm less common of a bullet than a 6.5? i guess all the .243 guys are having a hard time finding things to fit down their barrel. Both bullets have equal avalibility
jason41987
member
- Joined
- Apr 10, 2012
- Messages
- 1,293
hmm.. just seems to be a lot more popularity with 6.5mm rifles dating back further.. 6.5x55mm being one of them.. but after looking on midway at their selection of rifle bullets there is a larger selection in 6mm bullets, so i was off on that
i havent paid much attention to the 6mm cartridges, dont see many people speak out of them.. is there any other good 6mm options outside of the 6mm AR worth looking into as well?
i havent paid much attention to the 6mm cartridges, dont see many people speak out of them.. is there any other good 6mm options outside of the 6mm AR worth looking into as well?
HorseSoldier
Member
No. That's the issue various people have pointed out -- outside the AR, you simply don't have a lot of options besides the major cartridges, and maybe 6.8 SPC. For what the market can actually provide for, without a massive budget to pay for it, practical options across platforms are limited.
Which begs the question is this a practical project, or more of a theoretical one?
Which begs the question is this a practical project, or more of a theoretical one?
jason41987
member
- Joined
- Apr 10, 2012
- Messages
- 1,293
oh its a project, but will take place over a number of years converting one rifle at a time... ill have to outsource for custom barrels needed to convert them
CraigC
Sixgun Nut
For whatever strange reason, you're gonna fart around and make me order a 6.8 upper for my AR. 
The 6mm cartridges have a much longer history in the US than the 6.5mm's by a great margin. The 6.5x55 has a kind of cult following, but has never been hugely popular and it's really only been in the last decade or so that the idea of a 6.5mm has caught on here. On the other hand, the 6mm Lee Navy was a prototype military cartridge from the late 1800's that was really ahead of its time but it began the 6mm "thing" in the US. The 6mm-06 has been around for close to 100yrs but never really caught on because the case capacity is really too much for the 6mm bore. The .243 Win has been one of the most popular hunting cartridges in the US since its introduction. The US Army evaluated a 6mm cartridge for light machine gun use in the 60's (6mm SAW) but decided to stick with a standardized cartridge.
There are several 6mm wildcats based on various cartridges being chambered currently in the AR, but the good ones are based on either the Grendel or the 6.8SPC case so you run into the limitations of bolts, brass and mags all over again.
The BEST 6mm option, and really one of the best non-5.56 options in the AR with regard to parts interchangeability and availability is the 6x45, as I mentioned in my first post in this thread. It is nothing more than a .223 case necked up to 6mm and it has been around since about 5 minutes after the .223 was introduced. The only thing that has to be changed from a rifle chambered in .223/5.56 is the barrel. It has more power than the 5.56 and is capable of firing a heavier bullet. Magazine length is the limiting factor on bullet length, but the available 6mm bullets that will fit have better BC's than most of the 6.8 bullets that will fit in the mag. The only drawback to the 6x45 is that no commercial ammo has ever been loaded for it, so you have to handload. The reality is that at the current moment if you want a ready supply of Grendel or 6.8 you have to handload as well so this isn't an issue. The advantage that the 6x45 has over those others in this regard is that 6mm bullets are plentiful and cheap and that the brass, neither common, affordable nor capable of being made from any other common cartridge for the 6.8 or Grendel, is made in a single necking operation from .223/5.56 brass, the cheapest and most plentiful brass on the planet.
If you decide that you have to go down this road and spend (waste) all this time, money and effort just to be different (defeating the entire purpose of standardization in the first place, but whatever) the 6x45 makes the most sense by far.
HorseSoldier
Member
A 7mm-08 and .260 AR-10s would be pretty interesting, though I don't know who, if anyone, is making non-7.62x51 AR-10 uppers.
Plenty. DPMS makes them in .243, .260, 6.5 Creedmoor and .338 Fed at least. I believe the Remington R-25 (made by DPMS) is available in 7-08 as well. All you need is a barrel blank and a smith to contour and chamber it for you and any cartridge with a .473" case head and less than 2.8" in OAL is easy.
MTMilitiaman
Member
Some of your assumptions have me puzzled. You ask for an intermediate powered cartridge, but suggest that the 7.62x39 might not have enough range. From my experience with that cartridge, I can assure you; if you need more range than that cartridge can provide, you don't need an intermediate powered round.
The 7.62x39 certainly isn't a barn burner, but I think it gets a bad rap in the range department. I zero my AKs and my SKS at 200 yards, and have no problem getting conistent hits with iron sights on five gallon buckets at 300 yards. At that range, the cartridge has the mass, velocity, energy, and momentum of most popular .357 Magnum self defense loads at the muzzle. If you need more than that, you need a full power battle rifle round.
And lets face it, 300 yards is going to be a long shot for you. The average engagement range in Iraq is only 60 meters, last I heard, and that's if you're a front line combat soldier. The average engagement range for a law enforcement marksmen is something like 75 meters. Again, thats if you're in a uniform. More than likely you're a civilian, in which case, you're going to have a hard time finding a situation where you will be called to engage, legally, beyond 25 meters.
And what you get with the 7.62x39 is greater effectiveness at these ranges. With a standard bullet weight twice that of the poodle shooters, you have more to work with. Depending on what you're going for, you can be much better equipped to blast through vehicle bodies and windscreens, cinder blocks and light masonry, and wood or foliage. The standard FMJ round for the stubby Russian round can pass through a typical unfilled cinder block or a foot of pine and still be lethal. On the other end of the spectrum, the right JHP or one of the newer rounds on the market, like the Hornady SST round, delivers terminal performance and fight stopping ability the 5.56 can't touch.
When you consider effectiveness, cost and availability, and range, I think the 7.62x39 is the best intermediate powered assault rifle round existent. There are some that have better exterior ballistics and even better effectiveness, such as the Grendel or the SPC, but they haven't attained the availability or economy of the Soviet round.
What it really comes down to is the platform you prefer. If you like the AR, then the poodle shooter or one of the less common higher caliber/performance rounds like the aforementioned Grendel, SPC, or the Blackout/Whisper, which in its supersonic loads is a virtual ballistic twin to the older Soviet round. I like the AK, and in an era when a lot of people seemingly strive to make their rifles more like SMGs, I still like my rifles to be able to do "real rifle" things, like shoot through stuff or reach and touch, so I go with the 7.62x39 for all the up-close and personal stuff (alongside a pair of Glocks and a Mossberg 590) and a an M1A in 7.62x51 for the reach and touch stuff.
The 7.62x39 certainly isn't a barn burner, but I think it gets a bad rap in the range department. I zero my AKs and my SKS at 200 yards, and have no problem getting conistent hits with iron sights on five gallon buckets at 300 yards. At that range, the cartridge has the mass, velocity, energy, and momentum of most popular .357 Magnum self defense loads at the muzzle. If you need more than that, you need a full power battle rifle round.
And lets face it, 300 yards is going to be a long shot for you. The average engagement range in Iraq is only 60 meters, last I heard, and that's if you're a front line combat soldier. The average engagement range for a law enforcement marksmen is something like 75 meters. Again, thats if you're in a uniform. More than likely you're a civilian, in which case, you're going to have a hard time finding a situation where you will be called to engage, legally, beyond 25 meters.
And what you get with the 7.62x39 is greater effectiveness at these ranges. With a standard bullet weight twice that of the poodle shooters, you have more to work with. Depending on what you're going for, you can be much better equipped to blast through vehicle bodies and windscreens, cinder blocks and light masonry, and wood or foliage. The standard FMJ round for the stubby Russian round can pass through a typical unfilled cinder block or a foot of pine and still be lethal. On the other end of the spectrum, the right JHP or one of the newer rounds on the market, like the Hornady SST round, delivers terminal performance and fight stopping ability the 5.56 can't touch.
When you consider effectiveness, cost and availability, and range, I think the 7.62x39 is the best intermediate powered assault rifle round existent. There are some that have better exterior ballistics and even better effectiveness, such as the Grendel or the SPC, but they haven't attained the availability or economy of the Soviet round.
What it really comes down to is the platform you prefer. If you like the AR, then the poodle shooter or one of the less common higher caliber/performance rounds like the aforementioned Grendel, SPC, or the Blackout/Whisper, which in its supersonic loads is a virtual ballistic twin to the older Soviet round. I like the AK, and in an era when a lot of people seemingly strive to make their rifles more like SMGs, I still like my rifles to be able to do "real rifle" things, like shoot through stuff or reach and touch, so I go with the 7.62x39 for all the up-close and personal stuff (alongside a pair of Glocks and a Mossberg 590) and a an M1A in 7.62x51 for the reach and touch stuff.
Last edited:
I don't think there is any single cartridge for multiple weapons which would make sense. The one that would make the most sense would the cartridge available in the given situation. At least on this continent that is most likely going to be 5.56
jason41987
member
- Joined
- Apr 10, 2012
- Messages
- 1,293
hmm... although the 6.8mm would be more difficult to convert multiple rifles to vs the grendel, i do like the 6.8mm more, especially with a 120gr bullet... so i think for all of the 5.56 and 7.62x39 length rifles, 6.8mm would be best
its not about availability of ammo, that doesnt matter to me, its about getting the best possible performance out of these size actions from a cartridge that performs better than either of them
as for .308 length rifles, i would use something else, like a cartridge based on the .308, or one that could be easily made from .308 or .30-06 brass like a creedmor or .243...
but for the smaller actions, i think 6.8 would offer the best all around package at a level higher than either cartridge
its not about availability of ammo, that doesnt matter to me, its about getting the best possible performance out of these size actions from a cartridge that performs better than either of them
as for .308 length rifles, i would use something else, like a cartridge based on the .308, or one that could be easily made from .308 or .30-06 brass like a creedmor or .243...
but for the smaller actions, i think 6.8 would offer the best all around package at a level higher than either cartridge
- Status
Similar threads
- Locked
