Newbie with a couple of questions

[mr10mm]

I am very seriously thinking of putting together a .300 fireball upper for one of my ar-15s.

I have been searching for an alternative to .223. I've been examining all my choices and I have weighed all the pros and cons:

.6.8 spc- have to buy brass $$$$ weird bullet size and weight needs odd size bolt head and odd ball magazines

6.5 grendal- excellent long range performance same issues as 6.8 spc but even pricier parts.

6.5 mpc- $600 for a barrel and brass forming in a pain

.300 fireball. 7.62x39 ballistics from a case thats easily formed from .223 or .221 and feeds from .223 mags and uses a standard .223 bolt head uses .30 cal bullets from 110-240 grns.


Here is my deal. I am not looking for a sub sonic round. I am looking for an alternative to .223 for 0-250 yard shooting from an ar-15 rifle. I see load data for 125 grn bullets approaching 7.62x39 in a 16 inch barrel.

My questions are:

1. who makes a 20 inch .300 fireball barrel if any? I'm looking for increased velocity over the 16s with 125 grn bullets

2. do i have to modify magazines to work or is there a specific magazine or magazines available that work with both .223 and .300 fireball?

3. for super sonic loads will I need an adjustable gas block or tube? I'm looking to shoot 110-130 grn bullets not the super heavy stuff.

what say ye?

[320pf]

6.5 mpc- $600 for a barrel and brass forming in a pain

You are right about the high price of the barrel. SSK (J.D. Jones) charged premium dollars for his products. However, the brass forming is no more of a paint than forming brass for the 300-221 Fireball (300 Whisper). I think that all you do is size .223 brass, pushing the shoulder back a bit and trim to length. This is the way I make my 300-221 Fireball brass. Here is a link showing how I am currently making my brass.

http://www.quarterbore.net/forums/showthread.php?t=1763

.300 fireball. 7.62x39 ballistics from a case thats easily formed from .223 or .221 and feeds from .223 mags and uses a standard .223 bolt head uses .30 cal bullets from 110-240 grns.


Here is my deal. I am not looking for a sub sonic round. I am looking for an alternative to .223 for 0-250 yard shooting from an ar-15 rifle. I see load data for 125 grn bullets approaching 7.62x39 in a 16 inch barrel.

My questions are:

1. who makes a 20 inch .300 fireball barrel if any? I'm looking for increased velocity over the 16s with 125 grn bullets

2. do i have to modify magazines to work or is there a specific magazine or magazines available that work with both .223 and .300 fireball?

3. for super sonic loads will I need an adjustable gas block or tube? I'm looking to shoot 110-130 grn bullets not the super heavy stuff.

what say ye?

1.) If you want a 20-inch barrel you are going to have to order one. I would suggest that you call Noveske Rifleworks. He made a 16-inch barrel for me and it is one of the most accurate barrels that I have ever shot.

Why do you think that you need a 20-inch barrel? I can get 2250 fps from my 16-inch barrels without pushing the pressure limits. If I push the pressure limit, I can get 2350 fps. With the rifle sighted in 3-inch high at 100 yards, you will have a direct hold out to about 220 to 230 yards.

2.) No. You should not have to modify the standard AR15 mag to make it work. I would suggest that you chance the green follower to magpul follows and add heavy duty mag springs. I did this and the reliability increased significantly. I also use the same upgraded mags in my 5.56mm AR15 as well.

3.) If you are going to just shoot super sonic loads you can probably get by without using an adjustable gas block or gas tube. The question is do you want the gas port in the carbine position or the pistol position.

The pistol gas port position gives you a bit more flexibility with being able to shoot both sub-sonic and super-sonic loads without having to go to an adjustable gas port. I have found a gas port diameter that works without any adjustments for both sub-sonic and super-sonic loads. Here is the post

http://www.quarterbore.net/forums/showthread.php?t=1784

The carbine gas port position gives will shoot super-sonic loader a bit better. But if you want to be able to shoot sub-sonic loads you have to open the port diameter quite a bit. Thus you will need an adjustable gas block or gas tube to close the gas volume down when you shoot super-sonic loads.

If you have any additional questions just ask.

320pf

[GMC]

I'm looking for the dimensional data and load data for the 6.5x42 MPC cartridge. Any ideas?

[pud-knocker]

Here is my deal. I am not looking for a sub sonic round. I am looking for an alternative to .223 for 0-250 yard shooting from an ar-15 rifle. I see load data for 125 grn bullets approaching 7.62x39 in a 16 inch barrel.



I'm pretty happy with my 7.62x40mm

.223 brass, bolt, and mags

20" Noveske, 26gr 1680, 125gr TNT = 2,600fps and shoots 1/2 MOA

http://www.ar15.com/forums/topic.html?b=3&f=121&t=382761

[Spook]

I am very seriously thinking of putting together a .300 fireball upper for one of my ar-15s.

I have been searching for an alternative to .223. I've been examining all my choices and I have weighed all the pros and cons:

.6.8 spc- have to buy brass $$$$ weird bullet size and weight needs odd size bolt head and odd ball magazines

6.5 grendal- excellent long range performance same issues as 6.8 spc but even pricier parts.

6.5 mpc- $600 for a barrel and brass forming in a pain

.300 fireball. 7.62x39 ballistics from a case thats easily formed from .223 or .221 and feeds from .223 mags and uses a standard .223 bolt head uses .30 cal bullets from 110-240 grns.


Here is my deal. I am not looking for a sub sonic round. I am looking for an alternative to .223 for 0-250 yard shooting from an ar-15 rifle. I see load data for 125 grn bullets approaching 7.62x39 in a 16 inch barrel.

My questions are:

1. who makes a 20 inch .300 fireball barrel if any? I'm looking for increased velocity over the 16s with 125 grn bullets

2. do i have to modify magazines to work or is there a specific magazine or magazines available that work with both .223 and .300 fireball?

3. for super sonic loads will I need an adjustable gas block or tube? I'm looking to shoot 110-130 grn bullets not the super heavy stuff.

what say ye?

Supersonic?.... .308 X 39, 7.62 X 39 loaded with .308 bullets,redding dies have a 308 sizer button included, reamer at PTG, magazines from CProducts, 15 twist barrel.
Making brass just isnt that fun any more.

[Fastshooter03]

I haven't checked into the specs on a 7.62x40 but If you're only going to shoot light 308 bullets you could probably come up with a longer version of the 30-221 since you can trim and form the brass to whatever length you want.
You'd have to look at AR mags to see how much room you have to work with in the shoulder(case) area but I think it could be done without too much fuss.
I am also wondering how much fun a 6.5 mpc or 7mm-221 would be.

Nick

[interceptor]

I have been searching for an alternative to .223.


As in an inexpensive alternative? How about 5.45x39? I'm currently buying 2160 round cases for $300 out the door, using it for my alternative 3-gun match rifle. Half the cost of .223 and I don't have to worry about picking up the brass.

[Artful]

As in an inexpensive alternative? How about 5.45x39? I'm currently buying 2160 round cases for $300 out the door, using it for my alternative 3-gun match rifle. Half the cost of .223 and I don't have to worry about picking up the brass.

+1 for alternative to 223 shooting...

or just get 7.62x39 upper if your looking for supersonic 30 cal.