222 Low-Drag

He hasn't answered since Friday before last. He's either offended or hurt by the lack of interest in secrets.

 

You're correct, it can be made by 222 or 223 (5.56) brass. 223 would take one more step.

As I've mentioned before, I wanted to test and be the first to fire my idea. I figured that if I had given up too much info here with all the vast knowledge and experience that someone could knock it out before I could. I have in the past asked a question here to a hurdle I needed to get past that also didn't get warm responses. I guess I understand that y'all do need more info if you're to help with suggestions. This site, not just the forum, has been so helpful with information and techniques. I don't post here much but I have read so much over the years. No, I don't need a pat on the head, just figured y'all would find it interesting. It wasn't designed for praise but to improve upon the current .223/5.56 down range capabilities.

We have talked about having to get the pressure tested. From what my gunsmith told me we would have to send in a chambered barrel along with some loaded rounds. Is this correct? Is there other ways to test chamber pressures? We have been vigorously watching for pressure signs. Been recording head growth. Case growth has been minimum, if any. Had trimmed some a little to short and can't get them to grow to trim-to length. But, we've only blown three so far trying to find the extremes; this could also be attributed to my loading inexperience.

The 22 Nosler is fast but lack the high BC bullets capabilities at AR mag length. The 224 is impressive but requires 6.8 spc mags and bolt. My 222 LD-AR utilizes std 5.56 bolt and mags, just needs a new barrel.

Just because it hasn't been done before why shouldn't we try??

 

Lol I'm not, just thought more here would find it interesting.

It is an extremely fun project. It started wondering why with the some of the high BC bullets why it hasn't been done before. Then I put it to paper and run figures. Took it to my gunsmith and he though I was crazy. We made a prototype. That got the ball rolling. To be honest I was trying to get as close as possible to the performance of the MK 262. Breaking that and then going even faster than the Valkyrie was exhilarating.

Before this I had no reloading experience. I have sat and BS with a buddy or the gunsmith while they loaded so yes this project forced me to dive in and an enjoying it. Not just because of this cartridge but I'm really liking messing with reloading my own. It hasn't gone without some errors and frustrations (dam crazy digital scales). Anyway yes I agree it is fun.

This site has been immeasurably helpful and will release all details when more testing is done. I have shared some things already I probably shouldn't have but by the replies I guess they weren't noticed.

I love riding too. There's other sayings that I'm familiar with. "There are riders that have gone down and there are riders that have yet to go down" (and I've gone down hard a few times). "Ride it like you stole it.'

 

Like what? I just can't give case measurements yet.

Are we sure that an AR can't? Wouldn't an adjustable gas block regulate gases?

We are on the fifth and sixth loadings with the bolt gun brass. Will be annealing again after cleaning and going again. Will see how long that lasts. As for AR brass I'm sure it won't last as long, it usually doesn't right?

 

Well, I don't know about that. I'm assuming your being funny. Naming it was simple. At the time the reamer, headspace gauges, and dies were being manufactured its name was 224 Low-Drag. Reason at the time was for the true dia. During this time Federal launched the Valkyrie. Not wanting it to seem like it was trying to ride on the coattails of the "newest and greatest" thing out I called and tried to get the name changed but was too late, the engraving was already completed. So I had the files officially changed but my tools are engraved 224. Using the 222 designation is to pay homage to a classic but with modern low-drag projectiles.

Agree we are in uncharted territory and are proceeding with extreme caution.

Thank you for mentioning monitoring the brass and chamber. More checks points will be good. I've been monitoring the heads and case length growth but not on the shoulder/neck. This will be added. Want to push this but don't want to destroy the rifles (or my face).

Water capacity is 25.5 - 26 depending on brass manufacturer. We have run on Quickload to give us data points but it's not going to be accurate for this project.

 

Sorry, just been real busy. Work & OT, scouting new hog territory (this place is infested) and Mrs.

 

It was half a joke. Names are important for commercial products.

The big thing you haven't told us is what your goal is. Are you hoping to privately standardize this like the 6.5 Grendel was by Alexander arms for example? Cause that's really expensive and difficult.

I'm betting that if you posted your reamer spec, someone could post a nearly identical one from somewhere in the past. The 222 was the parent of ENDLESS improved variants back when it was king of the hill in benchrest. I'm not saying that to discourage you, just suggesting that it isn't as novel as you perhaps think.

Another example: 6mm FatRat, 6mm Grinch, and I believe there is one more (maybe 6mm Long Range AR?). All nearly identical and developed independently of each other.

 

I understand your goal now. I thought you faded away. I hope you can get it pressure tested as that should be interesting.
Good luck.

 

Please excuse my ignorance. What exactly is 'datum'? Have read some on it but still don't understand. What's the difference between datum and headspace?

 

The short answer is that a datum is a reference point on a drawing or print to measure other dimensions from. In this case, it's 0.200" from the bottom of the case rim and nominally marks the spot where the chamber in the barrel stops supporting the case walls. The 0.200 datum is a standard on all cartridge prints, found reproduced in reloading manuals and such.

Edit:

Datum is a reference point
Headspace is a measurement

 

Thank you for defining that and making it understandable. I will be taking more measurements at that point. Thanks again.

 

SAAMI specifies a maximum rim diameter of .378" and depending on manufacturer new brass can be .373-.376". Concerning case head growth when would it be advised to toss the brass?

Would it be determined by where it started off new or .378 is max regardless off manufacturer?

Would it be safe to reload and run another if at .377-.378" ?

Thanks for any help.

 

Sorry I must have overlooked this post. Main goal was to produce a cartridge that would increase extended range performance compared to the 5.56x45 while still utilizing the standard STANAG magazine and M16 bolt. As for what to do with it after testing - I'm not sure.

When I sent in my cartridge print the reamer mfr looked it over while I was on the phone with him and he said this has had to be done before. He looked through files, asked someone to go find some others and eventually said it was unique, so we moved forward from there.

 

If the rim of the case is growing at all, then you're way over pressure. Your primer pockets will probably be loose and primers will probably not even stay in at that point. The 0.200 datum will swell before the rim will though and could happen before other signs become apparent too. Calipers won't tell much though. You'll want to measure the brass all at the same temperature and use micrometers to watch for real growth.

 

When we first started testing we were just looking for pressure signs, we took it all the way up till we had the first light ejector sign, it was barely noticeable. We were also watching case growth, which is minimal. After a couple reloads we popped a couple cases at the primer pocket while pushing it. After that we decided we needed more ways to look for changes in the brass so we started to monitor the rims. This has been a learning experience. After y'all suggesting to monitor the .200 datum we are going to start including that as well, the more the better. Being a novice at reloading I didn't know what to look for in the in seating of primers, after some reloads I've gotten a 'feel' for what's right. Some have gotten to the point where they seated with minimal resistance but none to the point where they fell out. I felt a crunch when seating a couple, that also could have contributed to the popped primer pockets. Again, learning as I go.

But when would you consider time to trash the cases?

Thanks for helping out.

 

For me it's when they feel like they slide right in as though there's no resistance, when using a hand primer. If you're using a press to prime with then the mechanical advantage can be a bit trickier to judge. I'm not obsessive about them staying real tight like some folks are, if they go in with even a hint of resistance, they're good to go for me but I run relatively low pressure. Takes 20 or more reloads to loosen the brass for me. With your higher pressure loads, a good metric might be how many reloads you get until they're noticeably looser. 3-4: you're way up there but a lot of folks run at that point with good gear and accept the cost of buying a lot of brass. 10: warm loads, but in the safe realm. 20+ is conservative loading that is well below max. If necks split, that doesn't count for pressure, but is a sign that your sizing die is doing too much sizing.

 

Wasn’t someone just booted from this sight for posting about unsafe loads in a Dasher?

I guess this isn’t apples to apples but jeepers its seems awful fast from a 20” barrel for a 222 case.

A 223 AI loaded on the stout side will shoot a 75 at maybe just a bit faster than what you have done here.

I’m thinking, like others have said, you need to figure out how to measure pressure before you continue to feed this thing.

Measure the case head expansion if any morning to see what you’re doing.

Can we see a pic of a fired case looking at the primer??

 

Thanks for the recommendation on when to retire the cases because of loose primers but my apology for not being clear that at what point should they be shitcanned because of case head growth?

Took y'alls advise and took some measurements today while prepping more cases. These are just from a few cases, will be including this with all further testing. Since I didn't take the .200 datum measurement beforehand I don't have any unfired from that batch so I took new brass measurement from another unfired batch. Noticed that there is some diameter variances even with new brass.

New: .372" (unfired - different batch)
Fired: .374" (multiple reloads - 5-6)
Smallest: .373" (multiple reloads)
Largest: .376" (multiple reloads)

Noticed that SAAMI specs show a max of .376" diameter at .200 datum line. Is that max parameter for manufacturer purposes?

I do understand this brass will not last many reloads because it's being pushed hard for testing purposes.

No signs of split necks so far, we have been only neck sizing bolt gun brass.

 

No pre existing data to go by, trying to find its limits.

Looking into options on how to establish chamber pressures. The gunsmith knows a fellow with a Oehler System 83. Seems like a good first step option. Does anyone here have experience with strain guages? How does the results compare to the CUP method?

Will try to get a pic added soon.

 

If you can’t find pre existing data for a case based off the 222 you’re looking in the wrong spots.

Or, you need to learn to extrapolate data from something similar.

Hopefully you don’t end up blowing up.