Breaking News* New AR15 .30 cal cartridge


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R.W.Dale
October 13, 2008, 02:40 PM
Yes I said AR15 not ar10

appears to be similar to the 308wssm wildcat

http://outdoorlife.blogs.com/thegunshots/2008/10/first-look-30-r.html

http://outdoorlife.blogs.com/thegunshots/2008/10/30-remington-ar.html


If it pans out I'll likely own one of these uppers within a year :evil:

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JesseL
October 13, 2008, 02:52 PM
I'd like to know how it performs with 150gr + bullets.

R.W.Dale
October 13, 2008, 02:59 PM
From the numbers given it looks as though it replicates 300Savage

Loosedhorse
October 13, 2008, 03:15 PM
Sounds like a .300 Whisper, very slightly changed.

R.W.Dale
October 13, 2008, 03:20 PM
the case head measures a huge .500

the 300fireball doesn't even outperform 7.62x39mm this new chambering is 400fps faster with the same 125g bullets

http://outdoorlife.blogs.com/photos/uncategorized/2008/10/13/slide0014.gif

JesseL
October 13, 2008, 03:29 PM
They're going to need some seriously well made bolts if they won't want them breaking off lugs left and right.

A .5" case head makes for a lot of bolt thrust.

Bartkowski
October 13, 2008, 03:30 PM
I wonder how reliable it will be with a case that fat.

JesseL
October 13, 2008, 03:34 PM
Well, Olympic has been doing .223 and .243 WSSMs for a while now, so it's clearly feasible to some degree.

R.W.Dale
October 13, 2008, 03:38 PM
supposedly the wssm ar15's are even more reliable feeding than a bolt gun or .223 ar due to the fact that rounds are loaded and fed from the magazine in the same fashion as a single stack handgun such as the 1911

Bartkowski
October 13, 2008, 03:56 PM
supposedly the wssm ar15's are even more reliable feeding than a bolt gun or .223 ar due to the fact that rounds are loaded and fed from the magazine in the same fashion as a single stack handgun such as the 1911


That very well could be the case, but it doesn't seem like the fat cartridges would feed well. I only have experience with .223 in AR's so I wouldn't know, I just figured they would be less reliable.

Z-Michigan
October 13, 2008, 04:03 PM
They're going to need some seriously well made bolts if they won't want them breaking off lugs left and right.

A .5" case head makes for a lot of bolt thrust.

Yes, definitely.

A fat case can be fed reliably. Taper and feed geometry matters a lot.

With this being so wide I guess the magazines will be single stack or just barely staggered?

Couldn't find any more info either on Remington's website or a google search. Very curious to hear more.

Here's an idea - why not neck this down to 6.8mm? Then you could get all the performance, and maybe even a bit more, that Remington originally (and inaccurately!) claimed for the 6.8mm SPC (called the Remington SPC by Remington, not by almost anyone else). Maybe you could even launch the 130gr and heavier .270 bullets at attractive velocities.

Let's hope this isn't another one where Remington's original velocity #s end up being 300fps optimistic.

R.W.Dale
October 13, 2008, 04:12 PM
If unsuccessful I could envision this case being used for a full line of calibers for ar15's pretty much supplanting the larger and more expensive ar10's role in hunting.

It's about time someone introduced some truly useful rounds for the ar15 platform, for some time now we've had small cased, high cap friendly rounds that don't really offer any big increases in performance needed for taking game at range. Then on the other end we have some huge cased heavy recoiling big bore rounds that are great for short range work but don't cut it at long ranges.

It's about time someone combined the two into a useful middle ground

gvnwst
October 13, 2008, 05:46 PM
well, looks like we finally get a good .30 cartridge for the AR. how would the ballistics on this compare to a 6.5g upped to .30? basically7.62x39 IMP.

If unsuccessful I could envision this case being used for a full line of calibers for ar15's pretty much supplanting the larger and more expensive ar10's role in hunting.


don't you mean 'successful':p

JesseL
October 13, 2008, 05:51 PM
don't you mean 'successful'

Nah, I think he meant it could turn out one of those cartridges that only finds success as the parent of others. .284 Winchester is a good example.

ugaarguy
October 13, 2008, 05:51 PM
It's about time someone introduced some truly useful rounds for the ar15 platform, for some time now we've had small cased, high cap friendly rounds that don't really offer any big increases in performance needed for taking game at range. Then on the other end we have some huge cased heavy recoiling big bore rounds that are great for short range work but don't cut it at long ranges.

It's about time someone combined the two into a useful middle ground
.30 AR is pushing a 125 gr. to 2800 FPS MV. Black Hills factory loaded 6.5 Grendel is pushing a 123 gr. SMK to 2475 from a 16" bbl. according to data here http://www.65grendel.com/faq.htm. I'd like to see what the .30 Remington AR case would do necked down to 6.5mm.

onebigelf
October 13, 2008, 05:53 PM
How is this an advantage over some of the big-bore AR rounds like the .450 Bushmaster or the .50 Beowolf?

John

BlkHawk73
October 13, 2008, 05:57 PM
*yakn* I'll stick with my time proven modls and cartridges. not zipped up by the latest whiz-bang super short ultra power magno load. Also not into the whole spray and pray (c'mon admit many do the quick repetitive shots while hunting method either. One well placed shot and all is good.
At least I know I won't get getting in line ahead of anyone for one of these.

gvnwst
October 13, 2008, 05:59 PM
How is this an advantage over some of the big-bore AR rounds like the .450 Bushmaster or the .50 Beowolf?


ever try to shoot a .50 beowulf 400yd?

I'd like to see what the .30 Remington AR case would do necked down to 6.5mm.

6.5 WSSM. from what i have heard, it beats the grendel, making about .260rem ballistics

Jason_G
October 13, 2008, 06:08 PM
This has "niche cartridge" written all over it, I think. Sounds interesting, but absolutely useless unless you own an AR. Many do, but probably not enough to make this a mainstream cartridge you can go pick up at Wally World.

I think reloaders will be the ones who will get the most use out of this if it comes to fruition.

I reserve the right to be wrong though :D

Jason

m700m
October 13, 2008, 06:15 PM
i would hate, at this time, to stock-up for future feeding of that baby.

W.E.G.
October 13, 2008, 06:32 PM
All I have to say is DPMS LR-308.

I'm not at all interested in yet another odd-ball cartridge shoe-horned into a receiver designed for .223.

Dr. Tad Hussein Winslow
October 13, 2008, 06:37 PM
And around and around we go - wheeeeeeeeeeeeeeeeeeee!!

What WEG said.

It's just so, so, milquetoast. A bit more than a .300 whisper, so you cannot suppress it, but a bit less than .30-30 win, or about the same. Bleh, meh, etc. Expensive mags with low capacity. I foresee an EPIC FAIL poster with the .30 Remington on it within 1 year. :evil: But maybe not - I like Remington, so I HOPE they succeed.

Nolo
October 13, 2008, 06:37 PM
http://nolo84.deviantart.com/art/308-Shillelagh-99988325
My cartridge's case is longer, but it's significantly slimmer...
I wonder what pressures they are operating at?
All my data is just rough estimates using reference cartridges, such as the .30 HRT (same bullet diameter and weight), 6.5 Grendel (same case) and 7.62x39mm.
The Shillelagh would operate at a rather hot 55,000 PSI, like the SPC and, (I imagine) the HRT.
Oh well. I guess it's a good thing to come up with the same stuff as name-brand manufacturers...
'Course, I did do it way before them:
http://nolo84.deviantart.com/art/308-PPC-59477452
Just look at the submission date for that concept: July 9, 2007
:D
I don't know whether to be angry our proud...

gvnwst
October 13, 2008, 06:41 PM
I don't know whether to be angry our proud...


Laugh instead.
:D

Nolo
October 13, 2008, 06:46 PM
Oh, I am...
Funny bit is, I abandoned pursuing the .308-PPC a while back, because I didn't think it'd make a good assault rifle cartridge.
I only picked it up again very recently because I realize what awesome short-range performance you could get out of it.

W.E.G.
October 13, 2008, 06:47 PM
Remington would have a better chance of succeeding in the AR business if they would stop putting those garish camo-stickers on their guns and charging extra for it.

gvnwst
October 13, 2008, 06:49 PM
Funny bit is, I abandoned pursuing the .308-PPC a while back, because I didn't think it'd make a good assault rifle cartridge.

the '39 is a great one, so why wouldn't a IMP version be even better.

What are the ballistics on that cartridge compared to the one the thread is about? oh, wait, there's a hyperlink...:uhoh:

JesseL
October 13, 2008, 06:51 PM
All I have to say is DPMS LR-308.

I'm not at all interested in yet another odd-ball cartridge shoe-horned into a receiver designed for .223.

I totally understand the sentiment, but there is appeal in the idea of a potentially elk-capable autoloading rifle that weighs under 8 lbs too.

gvnwst
October 13, 2008, 06:55 PM
I totally understand the sentiment, but there is appeal in the idea of a potentially elk-capable autoloading rifle that weighs under 8 lbs too.


don't forget that it is a LR elk cartridge, not a short range like the .450 Bushmaster

JesseL
October 13, 2008, 06:57 PM
A bit more than a .300 whisper, so you cannot suppress it, but a bit less than .30-30 win, or about the same.

How is 125gr @ 2800fps less than or the same as what the .30-30 does? I can't find any .30-30 loads that push a 125gr bullet faster than 2450fps or so.

As far as I can tell, krochus is correct that it's about on par with the .300 Savage.

Nolo
October 13, 2008, 06:58 PM
All I have to say is DPMS LR-308.

I'm not at all interested in yet another odd-ball cartridge shoe-horned into a receiver designed for .223.
I have to argue with this on a couple of points:
The fact that the AR-15 is not all that amiable to larger cartridges has forced some serious inventiveness by ammo designers.
The 6.5 Grendel alone has proven that you can get the capability (range) of an old world battle rifle into a light, handy carbine.
The range of a K98 in the package of a Winchester '94? Oh by the way, it holds more than twice as many as both rifles combined? Sign me up!
Is it frustrating that the AR-15 is so inflexible (Oh, yes, I went there. Seriously, Stoner, you couldn't make the OAL 2mm longer?)? Yes.
But restrictions breed creativity.
The .30 RAR has all the capability of the .308 at the ranges most anyone will shoot at. Without the bulk and weight of an M14/AR-10/FAL, etc.

Dr. Tad Hussein Winslow
October 13, 2008, 07:12 PM
How is 125gr @ 2800fps less than or the same as what the .30-30 does? I can't find any .30-30 loads that push a 125gr bullet faster than 2450fps or so.

AccurateReloading website shows 2,529 for max load vel for .30-30 125s, and I found 2,475 and 2,630 fps for 125s elsewhere. Still, you are right, that is well behind 2,800, by about 200-300 fps more - pretty significant, so yeah, I guess more like .300 Savage, .30-40 Krag, or .303 Brit.

308sc
October 13, 2008, 07:37 PM
I think its false to claim .308 ballistics.

in a 125 grain bullet the .308 can push it at about 3100 FPS

this .30 AR can push it at about 2800 FPS

That gives the .308 a 300 FPS lead. The .308 handles heavy bullets well. I have loaded some 150 grains that are flying at 2765 FPS in a 22 inch barrel

I doubt this new caliber can hang with that.

Gewehr98
October 13, 2008, 08:22 PM
.30 AR is pushing a 125 gr. to 2800 FPS MV. Black Hills factory loaded 6.5 Grendel is pushing a 123 gr. SMK to 2475 from a 16" bbl. according to data here http://www.65grendel.com/faq.htm. I'd like to see what the .30 Remington AR case would do necked down to 6.5mm.

Am I the only one shooting a 20" AR variant anymore? :scrutiny:

This new offering from Remington only excites me from the aspect of maybe necking it down to 6.5mm. If it comes to fruition, and brass becomes readily available, I'll consider putting my current 6.5 SPC wildcat project on the back burner.

We need to review what chamber pressures this particular shortfat runs at, too. Lest we forget, the shortfats get their hypervelocity from chamber pressures considerably higher than their predecessors. So much more so, in fact, that handloaders often have trouble duplicating factory ballistics. :(

berettashotgun
October 13, 2008, 08:25 PM
SO.........what's so wrong with a 7mm/284-300 Savage?
Oh yeah, Brits did it awhile back.
It's what I'd want

JesseL
October 13, 2008, 08:29 PM
SO.........what's so wrong with a 7mm/284-300 Savage?

It won't fit in an AR-15.

Z-Michigan
October 13, 2008, 08:36 PM
IMHO, the problem is the platform. The AR-15 was designed for .223 or smaller cases and its magwell is limited to the OAL for those size rounds. Adding just 4-5mm to OAL would make a big difference in handling heavier spitzer-style bullets, of any caliber. Widening the magwell a bit would allow double stacking of fatter cartridges. And making the bolt a little bigger would increase its strength substantially. Of course, pretty quickly you basically have an AR-10. I don't see this as a bad thing. Why not just make AR-10's that aren't too expensive or too heavy, and fit almost any sane (for a lightweight rifle) cartridge into it.

gvnwst
October 13, 2008, 08:51 PM
just get a Cobb MCR. well, bushmaster now. interchangable mag wells in a AR platform

JWarren
October 13, 2008, 10:50 PM
Interesting concept.

First thing that I wonder about is what kind of throat erosion you'd get out of that cartridge. Its been my understanding that the WSSM cartridges tend to erode rather rapidly.

While I will follow this, I can't see me going this direction.

I keep thinking that by the time you "re-tooled" in this direction, you would not be too much cheaper than just getting an LR-308. You CAN get one for AR prices despite what some will tell you. Sure, they are heavy, but I don't hear of the issues people on this thread are already wondering about-- snapping bolt heads, etc.

For me, I still think I am going to stick with AR-15's for intermediate range (maybe a 6.8 upper for hunting) and the LR-308 for more power.


-- John

gvnwst
October 13, 2008, 11:01 PM
First thing that I wonder about is what kind of throat erosion you'd get out of that cartridge.

it wouldn't be bad, as the resean the WSSMs erode so fast is the amount of powder through so small a bore. with the bigger .30cal bore, it shouldn't be a problem, actually, it should be quite good barrel life.

JesseL
October 13, 2008, 11:07 PM
First thing that I wonder about is what kind of throat erosion you'd get out of that cartridge. Its been my understanding that the WSSM cartridges tend to erode rather rapidly.

Since it's running a much bigger bore than the .223 and .243 WSSM it's not nearly as overbore, and it's not pushing hyper velocities; it should have very good throat life.

JWarren
October 13, 2008, 11:16 PM
Quote:
First thing that I wonder about is what kind of throat erosion you'd get out of that cartridge.

it wouldn't be bad, as the resean the WSSMs erode so fast is the amount of powder through so small a bore. with the bigger .30cal bore, it shouldn't be a problem, actually, it should be quite good barrel life.

Quote:
Originally Posted by JWarren
First thing that I wonder about is what kind of throat erosion you'd get out of that cartridge. Its been my understanding that the WSSM cartridges tend to erode rather rapidly.

Since it's running a much bigger bore than the .223 and .243 WSSM it's not nearly as overbore, and it's not pushing hyper velocities; it should have very good throat life.


Thanks guys. :)


-- John

MachIVshooter
October 14, 2008, 12:19 AM
don't forget that it is a LR elk cartridge, not a short range like the .450 Bushmaster

That's laughable. I wouldn't call a round that makes less than 2,200 ft/lbs at the muzzle and uses squatty bullets with a crappy B.C. a "long range elk cartridge. Most people consider the .25-06 light for elk; My 117 grain loads with that cartridge retain 55% more energy at 400 yards than the .30 RAR, with a much straighter flight path. And the 117 gr. .257 has a much higher S.D.

.300 RUM is a long range elk cartridge. .300 Weatherby is a long range elk cartridge. This thing is a brush popper.

gvnwst
October 14, 2008, 09:59 AM
That's laughable. I wouldn't call a round that makes less than 2,200 ft/lbs at the muzzle and uses squatty bullets with a crappy B.C. a "long range elk cartridge. Most people consider the .25-06 light for elk; My 117 grain loads with that cartridge retain 55% more energy at 400 yards than the .30 RAR, with a much straighter flight path. And the 117 gr. .257 has a much higher S.D.

.300 RUM is a long range elk cartridge. .300 Weatherby is a long range elk cartridge. This thing is a brush popper.


alright, so it isn't a LR elk cartridge. Sorry for being wrong. it does however offer a lighter recoiling alternative to some big bore AR cartridges.
:)

R.W.Dale
October 14, 2008, 02:08 PM
http://outdoorlife.blogs.com/thegunshots/2008/10/30-rem-ar-some.html

MORE


.30 Rem. AR: Some Technical Info

A few people have asked for some technical specs on the new .30 RAR cartridge and, in no particular order, here are some of those answers.

Parent Case: The .450 Bushmaster. But the case head diameter was bumped up to .492” to prevent accidental chambering of other cartridges.

How about the bolt head? The bolt head is a modified .308 Win. bolt head that has been significantly beefed up to help handle the higher operating pressures generated by the .30 RAR. The .30 RAR is about a 55,000 psi cartridge vs. 38,000 psi for the 450 Bushmaster.

Last night while talking with DPMS President Randy Luth and Remington’s John Fink, who is the brand manager for the rifle division, they both said that the goal was to look at the AR lower and see how much cartridge they could fit in there.

Uppers: Remington said in no uncertain terms that it will (eventually) make uppers available for sale.

Rate of Twist: This is still being finalized, but right now they are playing with a 1-in-10” rate of twist and are getting pretty good results.

Cost: The suggested price for the R15 in .30 RAR is $1,199.

How’s it shoot? Well, it turned out that there wasn’t a functioning rifle available to shoot yesterday, so that question is one I can’t answer. But as soon as I get my hands on one, I’ll post a report.

Any other questions, let me know and I'll get back to you.

Update: Shelby at GunPundit has his own take on the new round and the Firearm Blog and SayUncle are both gathering info.

—John Snow

Organdonor
October 14, 2008, 02:31 PM
I'll stick with my time proven modls and cartridges. not zipped up by the latest whiz-bang super short ultra power magno load.

I agree... I'm fine with my two .30 AR's... my BAR-10 in 7.62NATO, and my Colt in 7.62X39mm.

elmerfudd
October 14, 2008, 02:49 PM
Instead of coming up with oddball cartridges, why not redesign the receiver instead? An AR 12.5? Make it a couple mm longer and a few mm wider, but not as large as an AR10. Either that, or figure out how to make the AR10 lighter. Bottom line is there's really no substitute for case capacity and I doubt that many people really want a single stack AR. That means you need more space and the only way to get it is with a bigger receiver.

R.W.Dale
October 14, 2008, 03:03 PM
Instead of coming up with oddball cartridges, why not redesign the receiver instead?

Because then the average ar owner would have to buy an entire rifle for ONE caliber..

I for one wouldn't bother and I doubt many others would as well

I doubt that many people really want a single stack AR.

I do,

I want a 400yd capable 30 caliber cartridge for hunting, in this format I could care less if it only holds 4 rds.

This may come as a shock to you but not everyone hides in the basement sitting on a crate of ammo cradling thier ar15 in thier arms waiting for civilization to collapse

2800 fps with a Nosler B-tip would roughly double my comfortable range for shootin bambi over my current 20" 7.62x39

taliv
October 14, 2008, 04:35 PM
i'm certainly pro-innovation. and even if this thing is a dud, maybe it will be the next step towards something really cool, like being able to neck it down to 6.5 or 6mm.

Howard Roark
October 14, 2008, 07:38 PM
i'm certainly pro-innovation. and even if this thing is a dud, maybe it will be the next step towards something really cool, like being able to neck it down to 6.5 or 6mm.

You are few years late, it's called a 6mm Hagar. The 30 Rem is nothing new.

ugaarguy
October 14, 2008, 08:58 PM
You are few years late, it's called a 6mm Hagar. The 30 Rem is nothing new.
You need to re-read the thread. .30 RAR is not .30 Remington. The cases are entirely different.

ugaarguy
October 14, 2008, 09:08 PM
Parent Case: The .450 Bushmaster. But the case head diameter was bumped up to .492 to prevent accidental chambering of other cartridges.
I'm thinking this means that existing .450 Bushmaster magazines will feed .30 RAR. This little cartridge is catching my interest. It may not be an Elk cartridge, but a 125 grain 30 cal bullet at the listed velocities sounds good for deer. I like the idea of an AR-10, but the size and weight make the reality of an AR-10 less desirable to me.

gvnwst
October 14, 2008, 10:33 PM
Parent Case: The .450 Bushmaster.


i thought it was the WSSM family?

Nolo
October 15, 2008, 12:24 AM
I honestly wonder why they used the .450 BM as the parent case...
I would be rather surprised if you couldn't do most of what this cartridge does using a lengthened 6mm PPC case... And you could double-stack it and use Grendel mags, too...

JesseL
October 15, 2008, 12:31 AM
I honestly wonder why they used the .450 BM as the parent case...
I would be rather surprised if you couldn't do most of what this cartridge does using a lengthened 6mm PPC case... And you could double-stack it and use Grendel mags, too...

You just invented the 7.62x39 improved, which would probably only run about 50-100 fps faster than the old 7.62x39 Soviet and wouldn't feed as reliably.

Nolo
October 15, 2008, 12:40 AM
You just invented the 7.62x39 improved, which would probably only run about 50-100 fps faster than the old 7.62x39 Soviet and wouldn't feed as reliably.
There is no way that's all you could get away with.
Let's look at some numbers:
6.5 Grendel: 123 grain @ 2650fps @ 45KPSI (20")
Not only are you drastically increasing the diameter of the bullet with the 7.62 version, which would increase velocity significantly, you're also increasing pressure to 55KPSI (6.8 SPC operating pressure) and the case length by 2mm. My guestimates run like this:
Add, say 75fps for the larger bullet.
Add 125fps for the higher pressure.
Add 50 fps for the longer case and much less bullet contained inside of it.
Subtract 75 fps so that the numbers are conservative.
What do you get?
2775 fps with the same exact bullet as the the .30 RAR out of a 20" barrel. To verify the numbers, I look at the .30 HRT (6.8 SPC necked up to 7.62), which is supposed to do 2700 fps with a 110-grain bullet. The estimates look valid.
As for feeding reliably, that's really an AR problem, not a cartridge problem. AR's got a lot of bugs...

aspade
October 15, 2008, 02:08 AM
The reason the Grendel has a lower operating pressure than the SPC is because the larger case head increases bolt thrust while removing bolt face material to fit it weakens the bolt. That is also the reason the SPC runs lower pressure than 5.56mm.

If you are dumping the buggy AR platform for one of your illustrations then there is no reason to be constrained by ether of these AR magwell compromises.

AA factory specs for the 6.5 / 123 / 19.5" are 2565 fps at 47-49k PSI.

Nolo
October 15, 2008, 02:25 AM
AA factory specs for the 6.5 / 123 / 19.5" are 2565 fps at 47-49k PSI.
I must say, the Grendel is one of the hardest cartridges I've ever seen to get reliable datum on...
:scrutiny:

If you are dumping the buggy AR platform for one of your illustrations then there is no reason to be constrained by ether of these AR magwell compromises.
Well, you wouldn't be dumping the lower, just the upper, which you'd have to change anyway.

The reason the Grendel has a lower operating pressure than the SPC is because the larger case head increases bolt thrust while removing bolt face material to fit it weakens the bolt. That is also the reason the SPC runs lower pressure than 5.56mm.
Bolt thrust and the bolt head can be compensated for, I imagine.
I thought the SPC runs at a higher pressure than the 5.56, not the other way around. I thought the 5.56 was 52KPSI and the SPC was 55KPSI.

BullpupBen
October 15, 2008, 02:44 AM
So what can this do that 6.5 Grendel or 6.8 Remington really can't? They can certainly take a deer..

shinz
October 15, 2008, 06:50 AM
Quote:
Parent Case: The .450 Bushmaster. But the case head diameter was bumped up to .492” to prevent accidental chambering of other cartridges.

I'm not even sure what the 450 Bushmaster is, but looking at the dimensions given in the Outdoor life blog link earlier in this thread, the parent case is more like an unrebated 284 Winchester or even a 376 Steyr, both of which seem to feature a .500" diameter base.
Steve

shinz
October 15, 2008, 08:22 AM
Letting google be my friend, I stumbled over this http://www.thefirearmblog.com/blog/2008/10/14/30-remington-ar-new-cartridge-for-the-ar-15/
article which seems to say that it is based on the 284 Win case in its rebated form, as is the 450 Bushmaster, & as speculated earlier, they will use 450 Bushmaster mags. Now I know what a 450 BM is .:D
Steve

gvnwst
October 15, 2008, 09:17 AM
Add, say 75fps for the larger bullet.


hey nolo, the differance between a 7mm-08 and a .308 is larger than that(from what i have heard), and you are making a even bigger jump.

Nolo
October 15, 2008, 12:04 PM
hey nolo, the differance between a 7mm-08 and a .308 is larger than that(from what i have heard), and you are making a even bigger jump.
I was being conservative. If I wanted to really stretch my boundaries, I'd say 150 fps for the bullet alone.
My point is, you can get great performance our of a .30 cal AR that is way worth it over 7.62x39mm. Oh, and you can still have 20+ rounds in the mag.

JesseL
October 15, 2008, 12:21 PM
If somebody can get me the case capacity of the .30 RAR and if Nolo can get me guestimates on the capacity of his 7.62x41 improved, I'll be happy to run things through QuickLOAD and get us some more informed guesses about the relative ballistics of these rounds.

gvnwst
October 15, 2008, 12:22 PM
Nolo:
well, it isn't exactly the same (he is running only 40k psi) but here almost exactly what you are thinking of:

http://http://www.65grendel.com/forum/showthread.php?t=2654

gvnwst
October 15, 2008, 12:24 PM
JesseL

look at the link, i think he says what the specifics are.

Nolo
October 15, 2008, 12:33 PM
If somebody can get me the case capacity of the .30 RAR and if Nolo can get me guestimates on the capacity of his 7.62x41 improved, I'll be happy to run things through QuickLOAD and get us some more informed guesses about the relative ballistics of these rounds.
Let's see...
I think the capacity of the 7.62-PPC is gonna be pretty easy to calculate..., the Grendel's case is almost cylindrical.
Alright, the 7.62-PPC's case capacity should be about 38.5 grains of water, 35.75 grains of powder.
I would have standard operating pressure for the 7.62-PPC to be the same as 5.56, and have it utilize a 125-grain bullet.
As for the .30 RAR...
Dunno.

Nolo
October 15, 2008, 12:34 PM
The link is busted.

gvnwst
October 15, 2008, 12:36 PM
nevermind i can't get it to work. see if copying the web address into your explorer does the trick.

Nolo
October 15, 2008, 12:36 PM
Ah, I see. You posted the link wrong.
Here is the right link:
http://www.65grendel.com/forum/showthread.php?t=2654
You're using multiple "http://"s

gvnwst
October 15, 2008, 12:37 PM
oh. well, never do that again.:uhoh:

Nolo
October 15, 2008, 12:39 PM
His cartridge is close, but I've still got 2mm of case and higher pressure on him.
I am pretty sure I can compensate for the increased bolt thrust (which won't be any more than 7.62 NATO, anyway, which is what we're competing against) with recoil buffer systems, and I imagine I could even fit those into standard-lower compatible upper.
Gonna need a whole new upper anyway, so why not?
Also looks like he isn't fitting those 155s into the AR-15s OAL, which means he isn't using AR-15 mags.

gvnwst
October 15, 2008, 12:41 PM
yeah, he has a bolt rifle chambered for it. good place to start though

Nolo
October 15, 2008, 12:45 PM
It is where I started.
Overall, I think my design is better. It can still use the big bullets without mags, just like his.
Not to mention he's only getting 2100 fps with 155s. I'd be willing to be I could get at least 2300...

JesseL
October 15, 2008, 12:47 PM
I am pretty sure I can compensate for the increased bolt thrust (which won't be any more than 7.62 NATO, anyway, which is what we're competing against) with recoil buffer systems, and I imagine I could even fit those into standard-lower compatible upper.

Nope.

Bolt thrust is a concern for the locking lugs, it has nothing to do with recoil.

Now it is apparently possible to deal with the bolt thrust issue, because the .30 RAR and WSSM uppers have already managed it.

This is going to be my last post here, I'm moving over to http://www.thehighroad.us

gvnwst
October 15, 2008, 12:47 PM
oh, and to compensate for bolt thrust, one do something like this:

http://bratrifles.com/


go to the new approach page. should make it strong enough.... if only they would sell them seperatly

Nolo
October 15, 2008, 12:49 PM
Bolt thrust is a concern for the locking lugs, it has nothing to do with recoil.
Silly me.
It can still be compensated for in the new upper receiver.
Bigger bolt. It's gonna need it anyway.

gvnwst
October 15, 2008, 12:51 PM
This is going to be my last post here, I'm moving over to http://www.thehighroad.us


i guess we should all start moving to decrease the lag effects of the mirroring or whatever.

gvnwst
October 15, 2008, 12:52 PM
nolo, did you check out the BCG system that site has?

Nolo
October 15, 2008, 12:52 PM
Is that what it is?
I am transitioning. It's just awful slow.

Nolo
October 15, 2008, 12:53 PM
nolo, did you check out the BCG system that site has?
Yep, it's pretty much what I was thinking of.

gvnwst
October 15, 2008, 12:57 PM
Is that what it is?
I am transitioning. It's just awful slow.


how is this working anyhow? i mean, it is a few hours behind with threads and posts, ect... sorry, i know this is off topic.

Nolo
October 15, 2008, 01:06 PM
Maybe just a mirror. Seems a little weird.
Y'know, I had a plan to stay off THR 'till this thing got resolved.
O' course, you and I were talking.
'N fact, here, I am gonna get off permanently.

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