6ARC

[Lincoln]

So y'all're saying I could probably get shit printing a reasonably consistent half inch group at 100 with the totally mixed and untrimmed range brass that 'drunken bumble bullets™' are made outta? :p
I can't even shoot that good, gonna be doing some learning.

Enjoying watching the saga of fancy wildcat loading for self-spotting whiz bang competition stuff.

I just don't mix headstamps (not even on pistols normally). My experience has been good bullets and a load tuned to the gun usually provide sub moa accuracy. Mixing headstamps changes pressures, velocity, and who knows what else.

If you are shooting factory loads buy several flavors and brands and shoot each. When you find something that works go buy enough to do what you want, hopefully the same lot.

If you're bored this guy talks a lot about the harmonics and other things. The harmonics are why I've always assumed you can get better groups out of hand loads. Find the spot where the vibration is the same each time. Maybe it's minimizing vibration. I've never worried about the fine details.

 

[Lincoln]

These guys are getting 3150fps from a 20" bolt gun, and 3275 from a 22 with 70g Blitzkings and Noslers. Maybe, but I'd have to see it myself.

Maybe. I'm shooting an 18" gas gun 223 with 75 grain slugs around 2650. Not even close to max pressure. A couple inches of barrel length would add maybe 200fps. Ramp the pressure up and drop the slug a 5% would probably get it in the ball park. That's with a 223. Lots of faster 22's around that could easily do that. 223 WSSM can easily do that and can be chambered in a gas gun as well.

A friend was getting 2900fps in a 30 WSSM shooting 210's. That's really impressive to me.

Almost all the published loads are pretty conservative on pressure. Hornady seems to be the most conservative. Publishing loads they need to make sure max is safe in pretty much any gun.

 

[Roc Doc]

Well I sized the Lapua Grendel brass using a RCBS small base die, then following it up with a mandrel for final neck tension, and trimmed for excess neck length. Shot 60 something rounds yesterday after dialing the gas block back to factory setting, and adding an Omega 300 on the end. It cycled just fine, but accuracy went from under 1" at 100 to just over 2". Brass came out dirty of course, but they all had a "stripe" around mid case, so I'll process these with the bushing die, and with the same load see if it tightens up. I didn't think I'd need to fireform with all the steps I took, but maybe so.

Here's a pic of the brass that came out using the Omega can. The brass all came out fine with no dented shoulders or necks or heavy swipes, so again, it will be interesting to see how this Lapua brass does on 2nd firing.

 

[Lincoln]

Are those getting as much blow by as they appear? I usually like to see a nice hard line where the neck seals. I see a line but there seems to be a lot of black.

Ive been meaning to reply all week. I was doing some research and found some information that may help. I'll post on your other thread.

 

[Roc Doc]

Are those getting as much blow by as they appear? I usually like to see a nice hard line where the neck seals. I see a line but there seems to be a lot of black.

Ive been meaning to reply all week. I was doing some research and found some information that may help. I'll post on your other thread.

I'm using a Superlative Arms adjustable gas block, and an Omega 300 can, along with a charging handle that is supposed to help with the gas in face issue, (which is does, but can't remember the mfg name right now). The brass has been cleaned and annealed, so I'll size/trim it and we'll see if this next loading gives the same results.

 

[Roc Doc]

Oh, and finally got it to cycle reliably by going to a heavier spring on the JP buffer, and cleaning the chamber and bolt more often.

 

[Lincoln]

Purdy.

vermin are out here and I'm trying to get ready. And my can just showed up and most of my barrels aren't threaded. And I'm almost out of match kings and switching to berger. Going to be busy.

Right now it looks like the new 7x300wsm may not get done for vermin season.

 

[Gatorgrizz27]

I picked up a pair of the Howa mini actions in 6mm ARC for when my boys are ready to deer hunt. Have about 700 6mm bullets on hand and found 4 boxes of brass in the form of loaded ammo from a buddy. Have dies also. Hopefully Lapua will make brass for this thing and it will be commercially successful. Need to figure out what I’m doing for stocks/chassis and scopes.

Everybody is talking about how great it is/should be, but it came out at the worst time possible and we have too many different cartridges already. At least it isn’t backed by Remington

 

[Roc Doc]

I picked up a pair of the Howa mini actions in 6mm ARC for when my boys are ready to deer hunt. Have about 700 6mm bullets on hand and found 4 boxes of brass in the form of loaded ammo from a buddy. Have dies also. Hopefully Lapua will make brass for this thing and it will be commercially successful. Need to figure out what I’m doing for stocks/chassis and scopes.

I heard that until the Ukraine shit-show is over, Lapua won't be making any brass for commercial sales.
As I said earlier, you can convert 6.5 Grendel to ARC in one step, you just have to trim afterwards.

 

[Gatorgrizz27]

I heard that until the Ukraine shit-show is over, Lapua won't be making any brass for commercial sales.
As I said earlier, you can convert 6.5 Grendel to ARC in one step, you just have to trim afterwards.

Yeah, I’m aware of that, just not really a fan of the wrong head stamps in a kid’s rifle. Won’t be loading them too warm, hopefully the Hornady brass will hold up for awhile.

 

[[486]]

I heard that until the Ukraine shit-show is over, Lapua won't be making any brass for commercial sales.

surely they aren't sending much good ammo over there?
seems like it'd be better to dump a bunch of stuff that can't be sold on the commercial market, like API 54r and all the surplus tracers

 

[Roc Doc]

Yeah, I’m aware of that, just not really a fan of the wrong head stamps in a kid’s rifle. Won’t be loading them too warm, hopefully the Hornady brass will hold up for awhile.

Completely understand that. It's just me shooting the rifle, so it's not really a concern for me. I've had some Hornady go south on me, and I'm not running them real hot either, about 2600 for my Hornady Load (LeverRevolution), so we'll see what my load comes in at for this converted brass.

 

[Roc Doc]

surely they aren't sending much good ammo over there?
seems like it'd be better to dump a bunch of stuff that can't be sold on the commercial market, like API 54r and all the surplus tracers

Well I think the Scandinavian countries want to be prepared if Russia makes a move on them, so they may be stockpiling. Don't have any proof, just what I've heard.

 

[Roc Doc]

OK, once fired converted Lapua Grendel brass
Fed GMM AR primer
LeverRevolution powder
Berger 105g Hybrids
84*
3600' DA
19% Relative Humidity
22" Shaw 1:7.5 twist barrel
SilencerCo Omega 300 can.

Looks like 30.2g gave me best SD and good velocity. I might load up another batch with 30.0-30.4 in 1g increments to see what happens. This gun will be used in PRS type matches, so as long as I'm sub-MOA that's sufficient. (The X'd out bulleyes were from another gun setting zero.)

 

[Weasel]

interested in this round after talking with a buddy and looking at his build but man seems like rifles in this round have dropped off.

 

[Lincoln]

Nice. I would run a couple in tenths up and down from the 29.2 and the 30.2. That vertical string is interesting.

 

[Lincoln]

interested in this round after talking with a buddy and looking at his build but man seems like rifles in this round have dropped off.

Bolt or gas? I think the ARC is a great option as a gas gun but there are better choices in a bolt.

But I have noticed that the current trend is high volume chamberings only. Kind of sucks.

 

[Roc Doc]

Bolt or gas? I think the ARC is a great option as a gas gun but there are better choices in a bolt.

But I have noticed that the current trend is high volume chamberings only. Kind of sucks.

AR15. Data says that at 1k, my 105 load has the.same.drop.as my 147 Creedmoor load. Impressive.

 

[Lincoln]

AR15. Data says that at 1k, my 105 load has the.same.drop.as my 147 Creedmoor load. Impressive.

I just had this discussion with my gunsmith friend. Both of us are 6mm fan bois. Most gas rounds are focused at 100 yards and down, The ARC is the opposite.

I think I'm going to do the fat rat. That extra 100-200fps is icing on the cake. But it is a ways off, the 7x300wsm is taking resources right now. Just bought some cheap Leica glass on sale and it seems very nice.

 

[Weasel]

Bolt or gas? I think the ARC is a great option as a gas gun but there are better choices in a bolt.

But I have noticed that the current trend is high volume chamberings only. Kind of sucks.

gas and what I'm shopping for now. but I'd rock a bolt as well. try to not end up with a multitude of rounds, not going great at the moment.

 

[665.0coupe]

gas and what I'm shopping for now. but I'd rock a bolt as well. try to not end up with a multitude of rounds, not going great at the moment.

There is no reason to run Arc in a bolt gun. It’s a round that is optimized to run in the constraints of an AR-15 mag well. When you build on a bolt gun you don’t have the same constraint, so don’t use a round that has compromises for limitations you don’t have.

 

[Roc Doc]

Nice. I would run a couple in tenths up and down from the 29.2 and the 30.2. That vertical string is interesting.

That, and the best group had the highest SD. Probably shooter in both instances.

 

[Lincoln]

That, and the best group had the highest SD. Probably shooter in both instances.

What is the deviation on that one? 10fps doesn't do much at 100. I was thinking it could be harmonics and you are close. Or rapid heat build.

That 30.5 looks like one pulled shot and something else.

I would be real tempted to run 30.0 to 30.8 in tenths. Maybe do the 30.5 to 30.8 first.

Also run a standard target that gives more aiming opportunities. The arrows and blocks really help to make sure your cant is consistent as well as the point of aim. I'll use the arrows, four blocks and the bullseye as ling as I have horizontal and vertical lines to use.

Fuck I just realized that was your deviation written there. I would run 30.2 to 30.5 in tenths. Are you seeing pressure signs at 30.5 yet?

 

[Roc Doc]

What is the deviation on that one? 10fps doesn't do much at 100. I was thinking it could be harmonics and you are close. Or rapid heat build.

That 30.5 looks like one pulled shot and something else.

I would be real tempted to run 30.0 to 30.8 in tenths. Maybe do the 30.5 to 30.8 first.

Also run a standard target that gives more aiming opportunities. The arrows and blocks really help to make sure your cant is consistent as well as the point of aim. I'll use the arrows, four blocks and the bullseye as ling as I have horizontal and vertical lines to use.

Fuck I just realized that was your deviation written there. I would run 30.2 to 30.5 in tenths. Are you seeing pressure signs at 30.5 yet?

The discussion on the Hide seems to say that the best results are near max load, which I've run into with other rounds as well. And yeah I loaded 30.0 -30.5 in 1g increments last night, so will test again after cleaning the gun and running a few foulers through it.

At 30.5 I'm getting pretty decent ejector swipes, but the primers look good.

I was actually impressed with the low SD's of all the groups. Not Bench Rest SD's, but pretty damn good for an AR, IMO.

 

[Lincoln]

I agree on the deviation. Bergers seem to like hotter in general.

After those you may try a couple above 30.5 and see what they run like.

 

[Lincoln]

I was browsing at "must haves" tonight and got reminded of something. A lot of the real high BC bullets don't hold together well at shorter ranges. When you think you are close see what the 400+ yard groups look like. You may be quite surprised.

I also forgot that I had decided I need to have a gas gun in a 25wssm. Just because it sounds like it would be cool. I setup a 75gr Vmax in my dads bolt gun running around 3800. On vermin it's aim at the head out to 500 yards and watch for red dust.

 

[Roc Doc]

I was browsing at "must haves" tonight and got reminded of something. A lot of the real high BC bullets don't hold together well at shorter ranges. When you think you are close see what the 400+ yard groups look like. You may be quite surprised.

I also forgot that I had decided I need to have a gas gun in a 25wssm. Just because it sounds like it would be cool. I setup a 75gr Vmax in my dads bolt gun running around 3800. On vermin it's aim at the head out to 500 yards and watch for red dust.

My local private range has added quite a few sub-moa targets, some out past 500, so I'll see what's up after I find the node I like. I'm shooting 105g hybrids so they have a little less BC than the LR target version, but they're still a very long bullet and I think I run the risk of a compressed load with my OAL (2.260). With the can and the extra 1 - 1.5g of powder, the velocities are about 150fps faster than what I was running before. I'll have to calc when it goes trans, again once I find the node i like, but I'm guessing about 1300yds.

 

[Roc Doc]

I picked up a pair of the Howa mini actions in 6mm ARC for when my boys are ready to deer hunt. Have about 700 6mm bullets on hand and found 4 boxes of brass in the form of loaded ammo from a buddy. Have dies also. Hopefully Lapua will make brass for this thing and it will be commercially successful. Need to figure out what I’m doing for stocks/chassis and scopes.

Everybody is talking about how great it is/should be, but it came out at the worst time possible and we have too many different cartridges already. At least it isn’t backed by Remington

I'm hearing Peterson will be making ARC brass later this year.

I was going to suggest the KRG Bravo chassis, but apparently they are not compatible with the Howa mini.

 

[Roc Doc]

I just had this discussion with my gunsmith friend. Both of us are 6mm fan bois. Most gas rounds are focused at 100 yards and down, The ARC is the opposite.

I'm not sure to what you're alluding. Bryan Litz has shown with shoot through targets that if a round is accurate at 100 it will be at 500 proportionally. And if it's not accurate at 100 it will be shit at 500 as well. Maybe I'm misunderstanding you here, because we routinely shoot 77g AR .223's out past 700.

 

[Lincoln]

I'm not sure to what you're alluding. Bryan Litz has shown with shoot through targets that if a round is accurate at 100 it will be at 500 proportionally. And if it's not accurate at 100 it will be shit at 500 as well. Maybe I'm misunderstanding you here, because we routinely shoot 77g AR .223's out past 700.

Their desired effective killing range. The ARC was the first lightweight round (that I know of) soecifically spec'd for longer ranges out of the 15.

Yes the 5.56 can be shot effectively at longer ranges but that wasn't the intent.

On the second part. That is somewhat what I was talking about. I'll see if I can make any sense.

Some bullets may be 0.5 MOA at 100 but don't hold that at 500. Maybe 1.5 MOA at 500.

Some high BC bullets may only be a .75 MOA at 100 because they haven't found their groove yet. From 100 out they stabilize and hold .25 MOA. You won't ever be less than the .75 MOA overall but there is less spread happening down range.

500 isn't the best judge because most modern bullets do very well at that range. After 500 is where some still hold it together and others start spreading.

My 243AI (when I could shoot good) was .375 MOA at 100 and .6 MOA at 1000 with 107 Match Kings. 105 Amax was .5 at 100 and .8 1000. So at 1000 the match king was better but Amax was holding better between 100 and 1000. If that stayed consistent at some point past 1000 the Amax would be more accurate.

I probably fucked that up but hopefully it makes sense.