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Discussion Starter #1
I recently bought some pulled SS109 bullets, and I'm trying to get a replica load for M855. Looking at load data, I've found that according to many sources, M855 velocity is actually above maximum specs for .223. Speer, for example, lists 25.0gr H335 as the max for .223, which only gets you about 2950 FPS. The fastest load with any powder they list is only 3025 FPS, still nearly 100FPS behind M855 specs.

Now, Sierra load data indicates that you can go up to 25.6gr H335 in an AR-15 and get 2950 FPS, though it appears as though their bullet has a somewhat longer bearing surface than M855, since it's not a boat-tail design, so that might account for why their load is significantly more powder with the same velocity. Also, I imagine the fact that they tested it in a gas-operated rifle probably sapped a little of the velocity from the round.

I've been loading 65gr GameKings with 25.2gr of H335, as per Sierra's recommendation. I feel relatively safe with that, since it's still .4gr below Sierra's listed max load. I'd like to load the M855 with the same powder charge, in the hopes that the ballistics will be similar. However, the fact that most other sources list that as being a bit too hot makes me kinda uneasy with using a charge that size with SS109 bullets.

Since both of these loads are gonna be set in my "SHTF" ammo can, I'd like to keep the M855 as close as possible to military specs, but I'd also like to avoid unnecessary wear and tear on the rifle. Am I pushing this too far? Why is Sierra's data so adventurous compared to Speer? Will shooting M855 at these pressures beat up my rifle in the long run?
 

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I wonder about this stuff too. I use Win 748 for 55 gr. SPs and Hodgdons says to use 26.3 grains. That is it . No minimum no maximum, just 26.3. Hornady says max of 26.4. I have loaded 26.6 and I have seen where guys are going up to 28+.
 

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Different cases , primers and test rifles will all effect the results between different reloading manuals. Also does the rifle have a .223 or 5.56 Nato chamber ?

Hogdon who makes the powder shows a max load of 25 grs.of H-335 with a 63 grain bullet.

I would back off this by at least a grain of powder for the 62gr. SS109 bullet as it has long bearing surface that can raise chamber pressure.

The last thing you want in SHFT ammo is a ruptured case stuck in the chamber from a hot load.

1 grain of powder either way isn't going to effect the terminal performance of the bullet much if at all.
 

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Discussion Starter #4
I've got a 5.56 chamber, which makes me a bit more comfortable with the higher pressures. It's only a 16" barrel, though, so I'm already at marginal performance when it comes to having a high enough velocity to fragment.
 

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I am curious as Foxbat is. Is it chambered for .223 or 5.56?
I selected the Colt LE6920 specifically for the M855 because it was chambered in 5.56 with a 1 in 7 twist.
 

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I see where others have asked which chamber is in your rifle, but yet to see where anyone has asked what kind of brass are you reloading? Commercial (.223) or NATO (5.56 and hopefully, Lake City)?

Considerable differences between the two, even if you fire-form a .223 case in a 5.56 chamber. You'll find that commercial brass is thinner, weighs less and has increased case volume. NATO has crimped primers (no effect on velocity, but it's an added step to deprime), has thicker case walls, weighs more and has less case volume than .223 commercial brass. Given the same load of powder, the NATO 5.56 brass will demonstrate increased pressure due to lower case volume. The thicker NATO brass will also bottle the increased pressures better.

Assuming this is being shot with an AR-15 variant, what length are the barrels, gas port placement (carbine, mid-length or rifle) and port size are you using to get the velocities you want to achieve? All have a significant effect on velocity. The bore is another factor. Two barrels, made the same day, can have variances as much as 100 f.p.s. If your particular AR-15's barrel isn't "fast", then no matter how much experimenting you do, you'll always begin with a 100 f.p.s deficit compared to "faster" AR's. It is statistically possible to own several AR's that don't reach the intended velocity while remaining within NATO standards of pressure.

Which leads me to this. 5.56 follows NATO standards. Commercial .223 ammo follow SAAMI standards. Most European cartridges adhere to C.I.P. standards. NATO spec for service ammo is closer to C.I.P. standards, which are higher than SAAMI allow. You've made achieving your goal more difficult to achieve if you're using commercial brass and also reloading to SAAMI specs.

However, you also stated that this ammo is for SHTF, which means it needs to be 110% reliable in feeding, firing and ejecting. Don't forget waterproofing the primer pockets and case mouths for longevity against moisture. This isn't some competition or varmint or even plinking load you're making here. This is SHTF ammo and they all go BANG. They also need to be consistently accurate at the ranges you intend to deploy them. In my opinion, I wouldn't care if my 5.56 reloads, in my rifles, impacts 2 MOA lower than someone else's combination so long as ALL of my ammo is shooting 2 MOA lower. I can easily compensate with more elevation in my sights. Besides, at the distances where 2 MOA matters, wind and target speed will be greater enemies than vertical drop.

I don't want you to misconstrue the intent of my message. I am not trying to dissuade you from pursuing your goal. It's a worthy one to achieve. I think every reloader that loads the service calibers has pursued the same or has given it some very deep thought over many cold nights. Some made it, while others didn't. If you find yourself amongst the ones who didn't, then hopefully it gave you a chance to shoot more often, while having a bit of fun along the way.

...And you'll have a full ammo can that qualifies for "SHTF"...
 

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I bought 3000 rounds of M855 for (Hopefully) long term storage for the possibility of SHTF. It may not be long term storage storage he is looking for, otherwise he would buy new.

But what if it continues for five years or more? I think Branth has a good point. If reloading is necessary during SHTF, now is the time to gain that knowledge.
 

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One doesn't have to buy brand new to achieve long term storage requirements for SHTF ammo. Reloaders can make it everyday.

If "what" continues for 5 years or more? SHTF? Then long term storage won't be an issue. But who knows when SHTF will begin? It may not even be in our lifetime. If it is in our lifetime, I'd like to know that it will work, even if it's 30 years from now. I've fired off many WWII ammo, in the past 10 years, that worked. With the added attention to detail that most reloaders have toward their hobby, I don't see why many can't achieve the same level of success, if that's the goal.

Buying brand new also doesn't give him the knowledge of reloading. It only exercises the wallet.

Nowhere in my post was I trying to dissuade him from reloading ammo. He already has the pulled SS109 bullets, the reloading equipment and the desire, so why shouldn't he attempt it? If he wants to replicate M855 performance, it's certainly doable, but there's the hard way and the not-so-hard way of going about it.
 

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Discussion Starter #9
I'm shooting mixed range pickup brass out of a 16" barrel, with a carbine-length gas system and a 1-9" twist. I realize that this makes me much less likely to be able to get 3k FPS with a 62gr bullet, but I don't really want to get 3k FPS. All I want is ammo that meets M855 specs. I don't have a chrono, either, so I really have no way of telling how fast the bullets leave my barrel, though I could probably guesstimate it by calculating bullet drop, though that likely wouldn't be too accurate.

My main concern is that I hear that below about 2700 FPS, M855 won't fragment, and therefore is gonna be no better than a through-and-through with a .22LR. I just want to make sure that my ammo fragments out to a fair distance away.

I suppose this is a minor concern, since the bulk of my set-aside ammo is 65gr GameKing, which is a soft point and will expand even at low velocities, but I planned on throwing some M855 ammo in there in case I had a scenario that required increased penetration.
 

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I see where others have asked which chamber is in your rifle, but yet to see where anyone has asked what kind of brass are you reloading? Commercial (.223) or NATO (5.56 and hopefully, Lake City)?

Considerable differences between the two, even if you fire-form a .223 case in a 5.56 chamber. You'll find that commercial brass is thinner, weighs less and has increased case volume. NATO has crimped primers (no effect on velocity, but it's an added step to deprime), has thicker case walls, weighs more and has less case volume than .223 commercial brass. Given the same load of powder, the NATO 5.56 brass will demonstrate increased pressure due to lower case volume. The thicker NATO brass will also bottle the increased pressures better.

Assuming this is being shot with an AR-15 variant, what length are the barrels, gas port placement (carbine, mid-length or rifle) and port size are you using to get the velocities you want to achieve? All have a significant effect on velocity. The bore is another factor. Two barrels, made the same day, can have variances as much as 100 f.p.s. If your particular AR-15's barrel isn't "fast", then no matter how much experimenting you do, you'll always begin with a 100 f.p.s deficit compared to "faster" AR's. It is statistically possible to own several AR's that don't reach the intended velocity while remaining within NATO standards of pressure.

Which leads me to this. 5.56 follows NATO standards. Commercial .223 ammo follow SAAMI standards. Most European cartridges adhere to C.I.P. standards. NATO spec for service ammo is closer to C.I.P. standards, which are higher than SAAMI allow. You've made achieving your goal more difficult to achieve if you're using commercial brass and also reloading to SAAMI specs.

However, you also stated that this ammo is for SHTF, which means it needs to be 110% reliable in feeding, firing and ejecting. Don't forget waterproofing the primer pockets and case mouths for longevity against moisture. This isn't some competition or varmint or even plinking load you're making here. This is SHTF ammo and they all go BANG. They also need to be consistently accurate at the ranges you intend to deploy them. In my opinion, I wouldn't care if my 5.56 reloads, in my rifles, impacts 2 MOA lower than someone else's combination so long as ALL of my ammo is shooting 2 MOA lower. I can easily compensate with more elevation in my sights. Besides, at the distances where 2 MOA matters, wind and target speed will be greater enemies than vertical drop.

I don't want you to misconstrue the intent of my message. I am not trying to dissuade you from pursuing your goal. It's a worthy one to achieve. I think every reloader that loads the service calibers has pursued the same or has given it some very deep thought over many cold nights. Some made it, while others didn't. If you find yourself amongst the ones who didn't, then hopefully it gave you a chance to shoot more often, while having a bit of fun along the way.

...And you'll have a full ammo can that qualifies for "SHTF"...
Form the .223 case to the 5.56 chamber? They are the same! The throat is the difference. SOME 5.56 cases are thicker not all. When you get into high performance rounds such as the .223/5.56 you better beware of case volume or you flirting with disaster. NATO/CIP check the pressure at the neck, SAAMI at the center of the case. The lack of leade in the throat is what causes the spike as much or more than hot loads.
 

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The first question should be... what S hits which F. That effects a lot of decisions - including ammo choice.
 

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I don't believe in trying to load to a certain FPS. I work up the load carefully checking for signs in the primer and case. Also what shoots BEST! 24.5 grains might be the most accurate than even 25 grains. You don't know until you target it and look for signs. The point is a load that shoots tight groups and is not at max speed is OK (better!). Flirting with max loads is always looking for trouble. I know as I used to buy H335 and H322 by the keg for Prairie Dog shooting. (used once fired mill brass and bought the bullets (.55 grain SP) by the 500 bulk box.)
 

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Discussion Starter #15
The first question should be... what S hits which F. That effects a lot of decisions - including ammo choice.
The whole point is that you have no way of knowing what a future crisis might look like. That's why I plan on having maybe 100 rounds of M855 in with the 300-400 SPBT loads. You never know when the additional penetration offered by the military ammo might come in handy.
 

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The whole point is that you have no way of knowing what a future crisis might look like. That's why I plan on having maybe 100 rounds of M855 in with the 300-400 SPBT loads. You never know when the additional penetration offered by the military ammo might come in handy.
.300 Win Mag with solids.
If only I could get depleted uranium...
 

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You bothered to quote my post, but apparently you didn't read any of it. My post is about the difference in brass, not the chambers, as the difference in chambers was already covered in previous posts in this thread. The very 1st sentence in my post gives it away. However, I'll respond to your post.

Form the .223 case to the 5.56 chamber? They are the same! The throat is the difference.
Fire-forming happens every time you pull the trigger. When reloading for semi-autos, most will FLR their fired brass to improve feeding. In bolt guns, many will avoid FLR and just neck size. Fire-forming takes place, irregardless, but case stretching is reduced in the neck sized cartridge, because there is less room for expansion until the chamber walls are hit. Even then, the brass springs back from the walls (.0002" -.0003") in properly annealed brass that stay within a safe pressure range.

The throat isn't the only difference, and you'll see why in the following paragraphs. If "They are the same!" as you claim, then it wouldn't matter which cartridge was dropped into either chamber, irregardless of the throat length. It's because .223 is NOT the same as 5.56, that throat length matters.

SOME 5.56 cases are thicker not all.
Given lot to lot tolerances, this may be true. However, NATO/CIP tolerances for 5.56 are looser than those given by SAAMI in regard to .223. Greater neck thickness is allowed for in 5.56 than for SAAMI specs in .223. Internal volume is slightly reduced in 5.56 compared to .223. Given these facts, you'll see that many reloaders will reduce their starting charges by 10% if using .223 reloading data for a 5.56 case when it's going to be fired in a .223 chamber. No such reduction is needed when shooting .223 cases in a .223 chamber.


When you get into high performance rounds such as the .223/5.56 you better beware of case volume or you flirting with disaster.
Absolutely agree. Too bad you ignore your own advice with the following.

NATO/CIP check the pressure at the neck, SAAMI at the center of the case.
This is true, but you fail to note the implications. Since NATO/CIP measure at the neck, it shows a difference of 22K psi over SAAMI. Unfortunately, many read this and think, "Well, if they were measured at the same point there would be no difference at all." How wrong they would be. So what does happen when you take the measurement at the center of the case instead of the neck? A difference of 8K psi or 6K cup is a very real possibility. It's not "the same" is it?

Now you should begin to understand WHY the 5.56 chamber has a longer throat than a .223 chamber. It's because of the combination of higher pressures and looser tolerances in NATO cartridges that a longer throat was given to the chamber. The longer throat reduces chamber pressure to stay within a safe pressure range before the bullet engages the rifling.

This is nothing new and actually shows the difference between American and European manufacturing styles. American rifles tend to have shorter throats than European made rifles and we saw it all the time back in the 70's. It was typical to see throats in European rifles measure a half inch and even longer before the rifling began.

The lack of leade in the throat is what causes the spike as much or more than hot loads.
I haven't seen any studies that one results more, less or the same as the other. It hardly matters. It's enough that I know, and others know, that either situation is dangerous and should be avoided.

Since mine are 5.56 chambered, I can use either. It's just one less thing I need to worry about. I don't know for certain if less stress leads to a longer life, but it certainly makes it more enjoyable.

Safe shooting.
 
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