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Old March 26, 2014, 01:03 AM   #1
Machineguntony
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cycling a semi or Full auto in 308

I am in the process of creating the cheapest possible round to cycle a gas fed .308.

My question is will a .308 with a 110 grain bullets cycle a gas fed semi or full auto? NATO specs call for 150 grain bullet. I'm worried that a light bullet will come out of the barrel too fast and not allow a build up of gas pressure needed to cycle the action. I have no experience in this issue.

Powder valley has .308 bullets at about $75/500 bullets. That's the cheapest I have seen.

I don't have the gun yet, so I can't make some rounds and test them. Won't have the gun for about another year, pending ATF approval.
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Old March 26, 2014, 05:27 AM   #2
steve4102
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It's the gas generated by the burned powder that cycles the action, not the bullet or bullet weight.

Depending on the action, a fast burning powder may not cycle the action due to lack of port pressure (gas). A very slow burning powder may cause damage to the action due to to much port pressure (gas).

Whether you can get the correct "Port pressure" with a 110gr bullet in a 308, duno.
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Old March 27, 2014, 02:50 PM   #3
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You can get the correct "port pressure" with any bullet weight, BUT you will very likely have to experiment with different powders to find the right one & amount.

Medium burning rate powders and starting loads are the place to begin, no matter the bullet weight.

As you don't have the gun, and won't for a while, I would not recommend loading any quantity of ammo for it, until you have the gun.

Stock pile components, but don't load any volume until you can test small batches in the gun. Once you have tested them and are happy with the results, THEN go into production mode for quantity.
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Old March 27, 2014, 07:29 PM   #4
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Thanks for the info, perfect. I couldn't find this info anywhere on the internet. Based on what you said, I ordered a large shipment of those 110 grain bullets. They're very cheap, making each finished round come out to about 30c (primer, powder, and bullets, and not including brass, which I don't count because I recycle it so much that the cost of brass becomes minimal).
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Old March 27, 2014, 11:29 PM   #5
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Pressure Curve

The gas port pressure curve is a critical part of internal ballistics for cartridges used in gas operated firearms. Gas operated weapons are generally tailored to a narrow range of powder burning rates and characteristics. If the port pressure is too low the weapon will fail to function and if to high the weapon may function too forcefully or rapidly causing extraction or cycling problems. [IMG][/IMG] sold it.

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Old March 27, 2014, 11:49 PM   #6
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http://www.xtremebullets.com/308-s/48051.htm

if your looking to save $$ give these folks a shot, i have been pleased with all of there products

plated of course, but i have been able to push them very close to rifle limits w/o failure, have not used the 308 btw, but did use the 762x39

being 150gr you will also save on powder a little bit
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Old March 28, 2014, 01:05 AM   #7
Machineguntony
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Awesome!

Thanks for the info, skizzums. The out of stock bullets are cheaper than the 110 grain bullets that I bought. I noticed that at 110 grains, I would be using on average about 10 more grains, than with a 150 grain bullet. So this is best of both worlds. Hopefully, those bullets go back in stock soon.

My only concern is that the bullets are flat points. Do you think they would have a problem feeding in an auto loader?
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Old March 28, 2014, 07:05 AM   #8
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I have a friend who is an FFL and does business with Hornady. Pick up a few LNL's, cut the UPC seal off the back of the box and resale them. They ran $325 new from Hornady last time and sold for more than that.

Fill out the "get loaded" form and include the UPC seal. They will send you 500 150gr JSP's (used to be 1000).

The only time in my life that getting bullets actually made me money.


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Old March 28, 2014, 04:44 PM   #9
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they are not out-of-stock, they just listing the 250 quantity out-of-stock, look at the 500 count right under it
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Old March 29, 2014, 01:34 PM   #10
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Thanks, Skizzums. I swore a few days ago, it was the other way around, where the 500 was out of stock and the 250 was in stock.

Before I buy a quantity, do you think the flat point will cause feeding problems in an auto loader? I'm not going to know for about a year, and due to shipping costs, it is usually most cost efficient to buy a large quantity. I don't want to be stuck with 10,000 of these bullets that I won't be able to use.

Thanks very much!
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Old March 29, 2014, 05:04 PM   #11
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i cant say for sure. I wouldn't see it being a problem, but an email to extreme would probably clear it up. I believe they started this line for the 300blk folks, they are also using ar's, so I doubt that will be an issuue
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Old March 29, 2014, 11:49 PM   #12
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.30 cal, 150gr flat point? isn't that the classic .30-30 bullet?
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Old March 29, 2014, 11:52 PM   #13
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True. That's a really good point. I'll call them Monday and ask them.
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Old March 30, 2014, 12:47 AM   #14
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Xtreme bullets doesn't seem to volume discount. Money per round is the same buying 500 or 1000. And shipping is always included.

It is a plated bullet which is very close to cast bullets. Without the metal jacket, it would be impractical to have pointed meplat. Therefore it would be either round nose or flat point. They choose flat point for whatever reason.

It is not the best bullet shape for auto loaders, let alone full auto, compared to fmj. But it seems OK in my sks. I am using their 7.62x39 that is also flat point.

-TL
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Old March 30, 2014, 09:02 AM   #15
steve4102
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Quote:
Originally Posted by Machineguntony
That's a really good point. I'll call them Monday and ask them.
Don't forget to ask them about Velocity.

According to their Web site these should not be pushed more than 1500fps. That's pretty slow for a 308 Win. round. To keep it under 1500 I would suspect you are not going to get the Port Pressure needed to cycle the action.

"We do not recommend velocities over 1500 FPS (Feet Per Second) and only a light taper crimp."

http://www.xtremebullets.com/Bullet-...nfo-s/1952.htm
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Old March 30, 2014, 11:30 AM   #16
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This may be applicable only to pistol bullets, which have thin plating by default. Rifle bullets probably have thick plating. I load both m1 carbine and 7.62x39 to 2000fps without problem.

-TL
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Old March 30, 2014, 12:05 PM   #17
steve4102
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Even at 2000fps, that's still way below Minimum load data for the 150gr bullet.

Keeping it down that low might require a fast Shotgun or Pistol powder, that would mean no port pressure and no cycling the action in a 308 Win.
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Old March 30, 2014, 12:45 PM   #18
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Quote:
Rifle bullets probably have thick plating. I load both m1 carbine and 7.62x39 to 2000fps without problem.
Unless they have plating thick enough to BE a jacket, I would say no.

Also bullets that still run ok at 2000fps might not be well suited for 26-2700fps.

Properly cast & sized lead bullets can do up to 2200fps (gas checked), however, I don't know anyone who would do that with a gas auto.

I have never used plated rifle bullets, so I cannot speak on them, other than to say that plating is, by its nature, more fragile than jackets are. I have used plated bullets in some handgun rounds, with satisfactory results, but I generally get as satisfactory results from unplated cast as well. And, for some applications I only use jacketed bullets.

I don't have any experience with full auto guns and reloads. I do have experience with full auto guns (one of the things I did for Uncle Sam was fix broken machineguns), and I do have experience with semi autos firing reloads.

In a .308 gas gun, you have two related, but different issues. Feeding/chambering the rounds is one, and the other is proper gas port pressure for the specific system used.

Some guns are self adjusting, meaning that excess pressure (at the wrong point in the time/pressure curve) is simply bled off, within limits.

Some guns are have manual adjustments (like the FAL), allowing you to adjust the gun to the ammo to a large degree.

Some others can only be run within the fairly narrow range of their design parameters, like the M1 Garand. (there are modifications where the operating range is enlarged, but Garands in GI configuration don't have the mod)

Just out of curiosity, when the ATF approves it, what gun are you getting?
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Old March 30, 2014, 05:48 PM   #19
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MGTony,

I'll have to go with AMP here .
Have never tried plated rifle bullets either.
I can say that I have seen plated 50 gr. Remington plated bullets come apart in the barrel -as in the bullets leaded the bore severely- of a new Ruger Swift that had a rough cut bore though.

Given you mention the year wait (for a machine gun?), I would look at the cost of the jacketed bullets as insurance, i.e. don't ask the gun to do what it was not designed and built to do.

Most guys shooting .308 use 150ish bullets, but at velocities above 2600.
Needed to cycle the gun.

The G3 might be an exception(my experience limited to a 91 that cycled and shot quite well with the 311332 and 26gr. of 5744, but man, did that gun get dirty!),
but my 14 and FAL (even with the adjustable gas settings) both require close to full power to cycle reliably in automatic mode.

You can get the FAL to work with lighter loaded ammo by dogging down the gas and keeping the butt tight to the shoulder, but that's not always possible on a crossing blackjack at full speed.
Simpler, for me anyway, to buck up for jacketed slugs and shoot them at 2650.
The 14 will feed fine with the 150 -170 FN, but the FAL will only feed them consistently from the right side of all of my magazines. I gave up trying to diagnose that one.

You might be on to something with shooting plated, maybe just too soon.
With advancements in the plating process toward heavier and tougher alloy coatings, might be we will see plated bullets getting a larger share of the market.

If you have some of the plated coming though, you might as well load up a couple of batches and go pay the gun a visit.

During the upcoming year, I would put some of your time into developing a relationship with local ranges to start piling up brass if you have not already done so.
Better to get it from a range than surplus G.I. that has been through a 60 or the U.S. MAG with the resulting case head stretch.
Autoloaders go through brass.
Also pick a precision mic from RCBS and get familiar with it to extend case life by minimizing the movement of the shoulder during sizing.

My .02, JT
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Old March 30, 2014, 05:52 PM   #20
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What exactly are you going to be feeding?
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Old March 30, 2014, 06:11 PM   #21
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If i remember correctly this is to feed a belt-fed M60. I think cast bullets, no matter how they were plated is a bad idea. Jacketed is the way to go.

30k+ for a gun. Id not risk plugging up gas ports and feed mech with lead bullets to save a penny. IMHO
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Old March 30, 2014, 09:11 PM   #22
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Many of the M60's have been well above $30k for a decade. You already said you have a year wait (likely closer to 8 months) I would see how many LNL's you can buy and resale in that amount of time, for the bullets.
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Old March 30, 2014, 10:50 PM   #23
Machineguntony
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Thanks for all the info, gents. It is a lot of info to process.

I am attempting to feed a Maremont M60. I spoke to Bob at Desert Ordnance, and he said they can upgrade it to an E6. The E6s have a short barrel, so there is also that variable.

The wait is actually about 11 months now, or about six months with efiling. The seller refused to efile, so I am looking at about 1 year, with the time to upgrade the gun. I am waiting on an MP5, M16A1, and an M16A2, and it's been about 10 months and Im still twiddling my thumbs.

Since the cost of shooting .308 is so high, I figured that I could save significant money by reloading the cheapest .308 possible. 1000 rounds per session isn't that much on a beltfed, and at 40c a round (which is my current projected lowest price possible with Hornady 110 grain), that's still a pretty expensive outting.

Since it's a belt fed machine gun, I'm not looking for MOA accuracy, but rather I am just seeking reliable cycling of the action.

Thanks for all the info, guys. This info is very helpful because there is very little written, even on the internet, about the M60. The most helpful M60 guide, which can be found on the machine gun price guide, details maintenance and care issues, but has no info on the ammo used. Everyone just says NATO spec 150 ball, tracer, etc, but there is zero info on reloading for any gas fed semi auto or full auto gun, much less info for an M60. Has anyone even tested what happens to the gas system if naked lead cast bullets are used? Does it get heavy lead depositing? What about the design of the bullet on cycling reliability? Almost zero info on the internet.

This whole thing is frustrating because I won't know the ultimate answer until about this time in 2015. Come 2015, I promise to write a report with pictures on the final result.
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Old March 31, 2014, 07:54 AM   #24
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If you already have spent around $100k on the toys you listed why fiddle around with cast bullets even if they might nor work?

I have ran cast lead in a full auto 45 before and I can promise that you have never seen leading so bad. It was a smooth bore in just a few thousand rounds.

What is it that you have against getting the free jacketed 150's from Hornady?
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Old March 31, 2014, 10:38 AM   #25
Machineguntony
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I have nothing against jacketed bullets. I am just trying to save money on ammo. I am not rich, I just have a really good job, and even if I was filthy rich, I would still want to save money on ammo. Shooting full auto, as most people know, is very expensive. I'm not looking to shoot naked cast bullets, rather just the cheapest possible bullet, and if plated cast will work, I would be happy shooting it.

I'm sure lots of other shooters are looking for a recipe on a cheap load, and the bullet cost seems to be the largest cost component of a load.

In the end, as is the case with reloading, in general, I don't ever save more money. I just am able to shoot a lot more because the loads are way cheaper. So the goal is really to be able to shoot more for the money.
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