6mm ARC (Bolt Action)

chungus · Jan 19, 2024

I gather that lever, varget, and CFE 223 seem to be the go to powders for this caliber. I have some on order but who knows when it will get here.

I am loading for a bolt gun and have on hand H4350, IMR4895, and CFE BLK. I can’t seem to find any load data with these powders. I am guessing it is because they are not ideal for this cartridge?

Have any of you loaded 6 arc with these powders and if so can you point me to some load data? I have some 58gr vmax and 95gr Berger vld hunting bullets I am anxious to try out. Really wanted to get something loaded today and take hunting this weekend.

morning would · Jan 20, 2024

@chungus Looking at the powders you have, h4350 is too slow and CFE BLK is too fast. I think IMR4895 would work, based purely on its burn rate, but I’ve never used it.

FuhQ · Jan 20, 2024

chungus said:
I gather that lever, varget, and CFE 223 seem to be the go to powders for this caliber. I have some on order but who knows when it will get here.

I am loading for a bolt gun and have on hand H4350, IMR4895, and CFE BLK. I can’t seem to find any load data with these powders. I am guessing it is because they are not ideal for this cartridge?

Have any of you loaded 6 arc with these powders and if so can you point me to some load data? I have some 58gr vmax and 95gr Berger vld hunting bullets I am anxious to try out. Really wanted to get something loaded today and take hunting this weekend.

CFE BLK is essentially a magnum pistol powder... It is WAY too fast, DO NOT ATTEMPT TO USE IT, you will blow up your gun, and possibly hurt yourself or someone else.

I think H4350 and IMR 4895 will be too slow for the ARC.

You will most-likely get the best performance with LeverEvolution. That's the one the performed best for me. Also, I recommend using CCI 400 (non-magnum) SR primers.

FuhQ · Jan 20, 2024

New video is up with the AGM Rattler TS50-640 thermal scope on the 16" Christensen Arms MPR 6mm ARC shooting @ 200 yards.

FuhQ · Feb 27, 2024

Any updates from any other 6 ARC bolt gun guys?

Deer season is over now, and coyote mating season is upon us... I will be going night hunting when I can with the new thermal.

turbo406 · Feb 27, 2024

FuhQ said:
Any updates from any other 6 ARC bolt gun guys?

Deer season is over now, and coyote mating season is upon

FuhQ said:
Any updates from any other 6 ARC bolt gun guys?

Deer season is over now, and coyote mating season is upon us... I will be going night hunting when I can with the new thermal.

Unfortunately nothing to report on game need to pack my heavy ass 110 tac out coyote hunting but found a load of 28 grains of varget and a 103 eldx shoots sub moa proven out to 1000, gave a buddy some of them to try and they shot sub half moa in his ar and decent in his 16 inch christeansen scout. 2580 fps outta my 18 savage which has proven itself to be a slow barrel. But have fallen in love with the arc and will definitely be building an ar soon for my primary coyote gun.

46caliber · Mar 14, 2024

chungus said:
I gather that lever, varget, and CFE 223 seem to be the go to powders for this caliber. I have some on order but who knows when it will get here.

I am loading for a bolt gun and have on hand H4350, IMR4895, and CFE BLK. I can’t seem to find any load data with these powders. I am guessing it is because they are not ideal for this cartridge?

Have any of you loaded 6 arc with these powders and if so can you point me to some load data? I have some 58gr vmax and 95gr Berger vld hunting bullets I am anxious to try out. Really wanted to get something loaded today and take hunting this weekend.

Digging up an old post, but Sierra posted some data around SHOT that included H4895. IMR4895 is a bit slower than H4895 but it is not as slow as CFE223. It should be just fine for the cartridge. I'm going to be trying it with some 107 Match Monster (bulk Nosler 107 purportedly).

46caliber · Mar 14, 2024

Bulletsmith said:
@Rob01 I’m using 29.0gr. Of N540 with a coated DTAC 115. Not pushing it hard. 2710 FPS. Barrel is 26in. Proof 7.5 twist. impact action.

It's nice to see someone got a DTAC above 2700fps. I was worried they'd be too long for this cartridge.

FuhQ · Aug 23, 2024

Bump…

46caliber · Aug 23, 2024

IMR 4895 burned too fast with the big heavy. Saw pressure earlier than I wanted. It would probably be fine with like 85 ish grain bullets. I'm currently running Win748 with the last of my 107s and will use it when I switch to Hornady 105s. Barrel really seems to like those in the pressure ladder I ran.

Birch7 · Sep 1, 2024

Anyone running alpha brass? Curious how primer pockets are holding with pressure.

FuhQ · Sep 1, 2024

Birch7 said:
Anyone running alpha brass? Curious how primer pockets are holding with pressure.

They’re sold out right now on their website, but I’ve been wanting to.

CollarChoke · Oct 13, 2024

I ran some initial velocity ladder testing with Alpha Brass, CCI BR4 primers and Hornady 108gr eld-m bullets. Results are out of a 20" 1:7.5 Benchmark barrel attached to a Zermatt Origin action.

EDIT: warning, these specs are over pressure don't use them, check your pressures with QuickLoad, Hornady's data for LeverEvolution is way over pressured.

Trim Length: 1.480"
Neck Tension: 0.003"
CBTO: 1.699" (zero'd on Hornady ogive gauge)
COAL: 2.250"
Powder: LeverEvolution

Results with 5 round groups:

29.2gr: mv 2699fps, sd 7.3
29.7gr: mv 2758fps, sd 3.5
30.2gr: mv 2806fps, sd 8.5
30.7gr: mv 2842fps, sd 12.1
31.2gr: mv 2890fps, sd 5.8

I was mostly just ballparking velocity and not chasing precision, but fwiw they all shot 0.5moa or below, which the 31.2gr load coming in at 0.3moa. These groups are too small to really conclude anything about precision so take that as you will.

I did have some consistent extractor shine marks on even the mild loads which I'm pretty sure are due to the headspace being a bit too roomy on this virgin brass. No other pressure signs, cases and primers look fine.

EDIT: went down the rabbit hole trying to figure what could be causing the extractor marks and turns out my freebore is seemingly very short (0.090") which I think is causing even Hornady factory COAL ammo to jam into the lands, which probably explains the higher than expected velocities and mild pressure signs I'm seeing on this 20" even with moderate loads. It shoots fine, but going to reach out to my barrel provider to get something spun up with some more freebore breathing room because I usually stay at least 0.020" off the lands and don't want to play pressure games with already temp sensitive powder.

Mr. Wolf · Oct 14, 2024

CollarChoke said:
I ran some initial velocity ladder testing with Alpha Brass, CCI BR4 primers and Hornady 108gr eld-m bullets. Results are out of a 20" 1:7.5 Benchmark barrel attached to a Zermatt Origin action.

Trim Length: 1.480"
Neck Tension: 0.003"
CBTO: 1.699" (zero'd on Hornady ogive gauge)
COAL: 2.250"
Powder: LeverEvolution

Results with 5 round groups:

29.2gr: mv 2699fps, sd 7.3
29.7gr: mv 2758fps, sd 3.5
30.2gr: mv 2806fps, sd 8.5
30.7gr: mv 2842fps, sd 12.1
31.2gr: mv 2890fps, sd 5.8

I was mostly just ballparking velocity and not chasing precision, but fwiw they all shot 0.5moa or below, which the 31.2gr load coming in at 0.3moa. These groups are too small to really conclude anything about precision so take that as you will.

I did have some consistent extractor shine marks on even the mild loads which I'm pretty sure are due to the headspace being a bit too roomy on this virgin brass. No other pressure signs, cases and primers look fine.

EDIT: went down the rabbit hole trying to figure what could be causing the extractor marks and turns out my freebore is seemingly very short (0.090") which is causing even Hornady factory COAL ammo to jam into the lands, which probably explains the higher than expected velocities and mild pressure signs I'm seeing on this 20" even with moderate loads. It shoots fine, but going to reach out to my barrel provider to get something spun up with some more freebore breathing room because I usually stay at least 0.020" off the lands and don't want to play pressure games with already temp sensitive powder.

Pure gold here, thanks for sharing.
Love the Alpha brass in 6.5 CM. Hoping that the OCD primer pocket helps with the brass life.
I'll be testing a 26" Criterion barrel and loading up a ladder with Staball Match powder and CFE 223 and Hornady 105 HPBT.
Hoping that my slightly lighter bullet and 26" barrel will allow for Staball Match to hit 2800+ without pressure signs.

CollarChoke · Oct 14, 2024

Small update:

After talking to my barrel provider and double checking SAAMI specs as well as their reamer print, my 0.090" freebore is definitely correct and for whatever reason Hornady seats their factory 6ARC long at 1.699" CBTO. Presumably because it's intended for gas guns with looser tolerances? Who knows. I'm into the lands at 1.666" CBTO so factory ammo and anything loaded to the same spec is jamming bullets into the lands.

My chamber is correct and exact, so I'll have to bump all my bullets down another 0.053" for 0.020" of jump, giving up quite a bit of case capacity which is going to drop down my posted velocities, but at least I'll get rid of the jam and pressure signs.

Would be curious to see if other folks here have more freebore to play with on their chambers (above SAAMI spec).

padom · Oct 14, 2024

CollarChoke said:
I ran some initial velocity ladder testing with Alpha Brass, CCI BR4 primers and Hornady 108gr eld-m bullets. Results are out of a 20" 1:7.5 Benchmark barrel attached to a Zermatt Origin action.

Trim Length: 1.480"
Neck Tension: 0.003"
CBTO: 1.699" (zero'd on Hornady ogive gauge)
COAL: 2.250"
Powder: LeverEvolution

Results with 5 round groups:

29.2gr: mv 2699fps, sd 7.3
29.7gr: mv 2758fps, sd 3.5
30.2gr: mv 2806fps, sd 8.5
30.7gr: mv 2842fps, sd 12.1
31.2gr: mv 2890fps, sd 5.8

I was mostly just ballparking velocity and not chasing precision, but fwiw they all shot 0.5moa or below, which the 31.2gr load coming in at 0.3moa. These groups are too small to really conclude anything about precision so take that as you will.

I did have some consistent extractor shine marks on even the mild loads which I'm pretty sure are due to the headspace being a bit too roomy on this virgin brass. No other pressure signs, cases and primers look fine.

EDIT: went down the rabbit hole trying to figure what could be causing the extractor marks and turns out my freebore is seemingly very short (0.090") which is causing even Hornady factory COAL ammo to jam into the lands, which probably explains the higher than expected velocities and mild pressure signs I'm seeing on this 20" even with moderate loads. It shoots fine, but going to reach out to my barrel provider to get something spun up with some more freebore breathing room because I usually stay at least 0.020" off the lands and don't want to play pressure games with already temp sensitive powder.

Charges over 30gr in your setup are over pressure... And if your jammed into the lands your even more over pressure than QL shows. your 31.2gr load @ 2890 is over 70,000psi... 6 ARC max sammi bolt gun pressure is 62,000 psi.. These numbers are are confirmed and trued from my 6 ARC testing.

The problem we are facing today is such good brass isnt showing the typical pressure signs we were used to. And Alpha OCD brass masks those signs even more.

You are WAY over pressure with Lever in your setup. Just an fyi. 31.2gr is right at 71,000psi.. and probably higher in your case being jammed..

padom · Oct 14, 2024

Ive said this before, those that want to shoot 6 ARC in a bolt gun need to use a bolt gun specific reamer with a much longer freebore to get that bullet up out the case... Or use the sammi reamer and then throat it out longer... The reamers being used right now were designed for AR's to fit 105/108 in an AR mag. This isnt an issue with bolt guns and leaves a lot of bullet jammed down in the case eating up capacity.

I did all of this with 224V when it came out. I designed and had a 224V bolt gun specific reamer made to shoot 90smk's with the bullet boattail/bearing surface junction above the case neck/shoulder junction...

CollarChoke · Oct 14, 2024

padom said:
Charges over 30gr in your setup are over pressure... And if your jammed into the lands your even more over pressure than QL shows. your 31.2gr load @ 2890 is over 70,000psi... 6 ARC max sammi bolt gun pressure is 62,000 psi.. These numbers are are confirmed and trued from my 6 ARC testing.

The problem we are facing today is such good brass isnt showing the typical pressure signs we were used to. And Alpha OCD brass masks those signs even more.

You are WAY over pressure with Lever in your setup. Just an fyi. 31.2gr is right at 71,000psi.. and probably higher in your case being jammed..

Heard yeah the pressure signs were bothering me to the point of going down the rabbit hole. My Lever powder charges came from the Hornady manual (31.2 max for a bolt gun) but I was surprised at the velocities out of the short barrel. Hornady brass and Alpha brass with the same loads ran damn near the same velocities FWIW.

For sure I'm way over pressure and glad I caught it in time. Actually just ordered the QL disc last night so I can run the pressure calcs myself going forward before going out and trusting anything I didn't calculate or measure first.

My initial mistake was skipping the OAL gauge check and blindly following factory ammo measurements assuming those were GTG with a SAAMI spec chamber and then rolling with Hornady max loads from the book.

I'm going to drop the bullets down off the lands and do an entirely new workup, probably will land around 2750fps for a safe and consistent load guessing around the 30.2gr mark.

Mr. Wolf · Oct 14, 2024

CollarChoke said:
Heard yeah the pressure signs were bothering me to the point of going down the rabbit hole. My Lever powder charges came from the Hornady manual (31.2 max for a bolt gun) but I was surprised at the velocities out of the short barrel. Hornady brass and Alpha brass with the same loads ran damn near the same velocities FWIW.

For sure I'm way over pressure and glad I caught it in time. Actually just ordered the QL disc last night so I can run the pressure calcs myself going forward before going out and trusting anything I didn't calculate or measure first.

My initial mistake was skipping the OAL gauge check and blindly following factory ammo measurements assuming those were GTG with a SAAMI spec chamber and then rolling with Hornady max loads from the book.

I'm going to drop the bullets down off the lands and do an entirely new workup, probably will land around 2750fps for a safe and consistent load guessing around the 30.2gr mark.

Thanks for sharing... I'm going to contact Northland shooter's supply to check what chamber specs they are using and confirm the measurement with a Hornady Comparitor when the barrel is delivered.

I was able to dig up another post in the Hide that talks about 6ARC bolt gun loads. Link below to consolidate information.

6mm ARC Bolt Gun Loadings

I have finished a 6mm ARC bolt action, and there's not a whole lot of data out. . Been fooling with the 6 arc in first a 18 inch and then a 22 in semi for the last year, so I have some baseline and experience with loading the cartridge. Did a shake down was with 10 rounds factory 108 eldm, and...

www.snipershide.com

Happy shooting.

CollarChoke · Oct 14, 2024

padom said:
Ive said this before, those that want to shoot 6 ARC in a bolt gun need to use a bolt gun specific reamer with a much longer freebore to get that bullet up out the case... Or use the sammi reamer and then throat it out longer... The reamers being used right now were designed for AR's to fit 105/108 in an AR mag. This isnt an issue with bolt guns and leaves a lot of bullet jammed down in the case eating up capacity.

I did all of this with 224V when it came out. I designed and had a 224V bolt gun specific reamer made to shoot 90smk's with the bullet boattail/bearing surface junction above the case neck/shoulder junction...

Do you know of anyone that will make a longer freebore 6ARC barrel? Blue Mountain Precision is my usual goto but talking to Eric their reamer is 0.090". I guess I can ask him if he can throat mine out more on the next one, but other options for quality 6ARC bolt gun barrels are always good to know about.

padom · Oct 14, 2024

CollarChoke said:
Do you know of anyone that will make a longer freebore 6ARC barrel? Blue Mountain Precision is my usual goto but talking to Eric their reamer is 0.090". I guess I can ask him if he can throat mine out more on the next one, but other options for quality 6ARC bolt gun barrels are always good to know about.

I do not know any smiths that have a bolt gun specific long freebore 6 ARC reamer right now. You could be the first... I can give you the print if you want and you can order one from Manson. Or have your smith order one. Let me run some numbers on my 6 ARC and take some measurements and make a print on what I think would be an ideal 6 ARC bolt gun reamer for 100-108gr pills.

FuhQ · Oct 14, 2024

padom said:
I do not know any smiths that have a bolt gun specific long freebore 6 ARC reamer right now. You could be the first... I can give you the print if you want and you can order one from Manson. Or have your smith order one. Let me run some numbers on my 6 ARC and take some measurements and make a print on what I think would be an ideal 6 ARC bolt gun reamer for 100-108gr pills.

What about one for running 110-115gr VLD/RDF style bullets, while still fitting perfectly inside the steel MDT 6mm ARC mags?

padom · Oct 14, 2024

Here what I have to ask.. Why run a 6 ARC then in a bolt gun??

There are already multiple reamers setup for all these different bullets, lighter or heavier 6mm bullets in a bolt gun, all the smiths have these reamers, Lapua, Alpha, Peterson brass all in 6BR??

Whats the reason to run 6 ARC in a bolt gun then? It was designed to run the longer, heavier bullets in an AR mag....

padom · Oct 14, 2024

FuhQ said:
What about one for running 110-115gr VLD/RDF style bullets, while still fitting perfectly inside the steel MDT 6mm ARC mags?

Guys dont even run these bullets in 6BR because of case capacity... So why would you want to run these bullets in a 6 ARC bolt gun with even less case capacity???

CollarChoke · Oct 14, 2024

padom said:
I do not know any smiths that have a bolt gun specific long freebore 6 ARC reamer right now. You could be the first... I can give you the print if you want and you can order one from Manson. Or have your smith order one. Let me run some numbers on my 6 ARC and take some measurements and make a print on what I think would be an ideal 6 ARC bolt gun reamer for 100-108gr pills.

That would be fantastic, thanks!

CollarChoke · Oct 14, 2024

padom said:
Here what I have to ask.. Why run a 6 ARC then in a bolt gun??

There are already multiple reamers setup for all these different bullets, lighter or heavier 6mm bullets in a bolt gun, all the smiths have these reamers, Lapua, Alpha, Peterson brass all in 6BR??

Whats the reason to run 6 ARC in a bolt gun then? It was designed to run the longer, heavier bullets in an AR mag....

Ah well in my case even factory ammo is too long for my freebore so I just want a little breathing room and the ability to play with jump to dive deeper into cartridge.

Why 6ARC in a bolt gun? Started out of curiosity, which morphed into getting dies and a bolt face for an Origin action I had laying around for a temporary build to play around with it. Then it shot so well, I made it a dedicated build, and now I'm just committed to making it work, you know how that goes.

I love everything else about it, it feeds fantastic, it shoots lights out with pretty much everything I've run through it (besides the pressure issues on my reloads), the 12-round MDT mags are tiny, and with Lever the velocities are great out of shorter barrels.

Going with a 6BR would make life easier I suppose, but from a hobby perspective it's just great fun to explore 6ARC in this way.

FuhQ · Oct 14, 2024

padom said:
Guys dont even run these bullets in 6BR because of case capacity... So why would you want to run these bullets in a 6 ARC bolt gun with even less case capacity???

I've been running Nosler 115 RDF's in my 16" Christensen Arms MPR 6 ARC for almost 2 years now, with excellent results. With Lever I'm getting 2,575 FPS MV. But slightly longer throat would be nice to loosen up some room in the case from not having to seat them so deep.

Rob01 · Oct 14, 2024

padom said:
Guys dont even run these bullets in 6BR because of case capacity... So why would you want to run these bullets in a 6 ARC bolt gun with even less case capacity???

I run 110 ATips in my 6 ARC bolt gun. Works great.

padom · Oct 14, 2024

Rob01 said:
I run 110 ATips in my 6 ARC bolt gun. Works great.

Rob, Im not saying it doesnt "work." But, Id say that 110 Atip certainly isnt optimal for a bolt gun and is way down in the case in a SAAMI 0.089"fb chamber. If we are chambering 6 ARC bolt guns, I dont see any reason why a 6 ARC bolt gun reamer isnt made just like we did with 224V a few years back...

Mike Casselton · Oct 14, 2024

Re the heavier bullets.
I've run 3000 112s though my 22" 6-BR. Even though they are slower, they just kill the 105 class bullets with trajectory at longer ranges.

padom · Oct 14, 2024

So I just took a bunch of measurements in my 6 ARC with SAAMI 0.089" freebore chamber using the 108 ELD you asked about...

I hit the lands in my chamber with a 108ELD @ 2.30" COAL.. So, first, if your jammed at 2.25" then something is off there...

I marked the boattail/bearing surface junction of the 108 ELD and laid it next to the 2.30" COAL round right out of my gun touching the lands. You can see where the junction is. Its WAY down in the case eating up capacity and giving you pressure much earlier than it would if we had an optimal bolt gun 6 ARC chamber/Reamer. Shit its down at the shoulder/body junction.

Now, I took another round and I moved that 108 ELD boattail/bearing surface junction out to just above the donut area neck/shoulder junction which is your optimal location for round. Rule is you always want to be above the donut.

Thats now 2.40" COAL and look how much more room you have in the case to optimize this round for a bolt gun.. Im talking to Manson right now and gonna have one made to test in my TL3 then Ill give my reamer to a smith to chamber barrels with just like I did with my 224V 85-90gr bolt gun reamer I designed... Optimal bolt gun 6 ARC freebore for 108 ELD measures about 0.180-0.190" fb

padom · Oct 14, 2024

Mike Casselton said:
Re the heavier bullets.
I've run 3000 112s though my 22" 6-BR. Even though they are slower, they just kill the 105 class bullets with trajectory at longer ranges.

Whats your speed on that load? I run all 28" 6BR's but I run 106 A-Tips and they are absolute lasers to 1000yds.

Rob01 · Oct 14, 2024

It's really not too bad. I load the 110 at .020" off and it's not overly deep in the case. I didn't order any special chamber so that is SAAMI.

padom · Oct 14, 2024

Rob01 said:
It's really not too bad. I load the 110 at .020" off and it's not overly deep in the case. I didn't order any special chamber so that is SAAMI.

View attachment 8524186

Is that from Josh? He used a 0.089" fb saami reamer? Not throated at all? If so, thats way better than the 108 ELD, 105 Hybrid and 107 SMK I measured in my Saami chamber Craddock used on my 22" 6 ARC RTR barrel.

Rob01 · Oct 14, 2024

padom said:
Is that from Josh? He used a 0.089" fb saami reamer? Not throated at all? If so, thats way better than the 108 ELD, 105 Hybrid and 107 SMK I measured in my Saami chamber Craddock used on my 22" 6 ARC RTR barrel.

Yup that's from Josh. I assumed he used a SAAMI chamber. I didn't ask.

padom · Oct 14, 2024

Can someone measure a loaded 6 ARC round with Alpha OCD brass for me? Whats your loaded neck diameter?

My loaded neck diameter is 0.2675" measured with a mic on 10pcs with Starline brass.

padom · Oct 14, 2024

Rob01 said:
Yup that's from Josh. I assumed he used a SAAMI chamber. I didn't ask.

Gotcha. I can ask him

padom · Oct 14, 2024

Rob01 said:
Yup that's from Josh. I assumed he used a SAAMI chamber. I didn't ask.

How long are those 110 A-Tips? Maybe they are just shorter than a 108 ELD...

Rob01 · Oct 14, 2024

padom said:
How long are those 110 A-Tips? Maybe they are just shorter than a 108 ELD...

They are 1.310" long. The loaded round is 2.355".

CollarChoke · Oct 14, 2024

Hrmm I wonder if my 6ARC modified case is off then, this is the first time I've used it. This is factory vs reload (hornady brass) COAL is 2.252" on both.

And this is where I should be to get off the lands 0.020 according my OAL gauge:

Padom: I'll load a piece of Alpha and get you that measurement in a sec.

padom · Oct 14, 2024

Rob01 said:
They are 1.310" long. The loaded round is 2.355".

Gotcha. So it looks like a shorter boattail, and long bearing surface.

CollarChoke said:
Hrmm I wonder if my 6ARC modified case is off then, this is the first time I've used it. This is factory vs reload (hornady brass) COAL is 2.252" on both.

View attachment 8524194

And this is where I should be to get off the lands 0.020 according my OAL gauge:

View attachment 8524201

Padom: I'll load a piece of Alpha and get you that measurement in a sec.

Yea so the base to ogive with your Hornady tool is just a datum line comparative measurement. But if your in the lands @ 2.25" with a 108 ELD thats short.. Even the Hornady reloading manual calls for a 2.25" COAL for 108 ELD's and they arent telling you to load jammed into the lands. You should be a good 0.050" off the lands at 2.25" COAL.

FuhQ · Oct 14, 2024

padom said:
Can someone measure a loaded 6 ARC round with Alpha OCD brass for me? Whats your loaded neck diameter?

My loaded neck diameter is 0.2675" measured with a mic on 10pcs with Starline brass.

Call, or shoot an email over to Tom @ Alpha. They'll gladly tell you what bushing they recommend.

padom · Oct 14, 2024

Rob01 said:
They are 1.310" long. The loaded round is 2.355".

Must just be the design of the A-Tips and the 108 ELD is just a really long bullet....

I just measured my 106 A-Tips and they are 2.38" COAL to the lands and my bullet boattail/bearing surface junction is almost in the same exact spot yours is in your picture with your 110 A-Tips.. just below the neck/shoulder junction.

I guess these 106-Atips are long. 1.321" long...

padom · Oct 14, 2024

FuhQ said:
Call, or shoot an email over to Tom @ Alpha. They'll gladly tell you what bushing they recommend.

yea Im not looking for what bushing to use. I want to know how much thicker the necks are, if at all, compared to Starline brass

With 6 ARC saami reamer, its got a 0.275 neck. My Starline loaded neck measures 0.2675.. Thats 0.0075" neck clearance, rightfully so on a chamber designed for an gasser..

But on a bolt gun, I like 0.002-0.0025 clearance per side (0.004-0.005") so when I have this reamer made, Ill order a 0.272 or 0.273 No Turn neck.. But my final decision on that will be based off what Alpha brass measured because thats your optimal brass for a dedicated 6 ARC bolt gun.

CollarChoke · Oct 14, 2024

padom said:
Can someone measure a loaded 6 ARC round with Alpha OCD brass for me? Whats your loaded neck diameter?

My loaded neck diameter is 0.2675" measured with a mic on 10pcs with Starline brass.

Getting 0.271" on 0.003" neck tension here

padom · Oct 14, 2024

CollarChoke said:
Getting 0.271" on 0.003" neck tension here
View attachment 8524208
View attachment 8524209

Interesting, so Alpha OCD necks are way thicker than Starline... 0.2675 vs 0.271...

padom · Oct 14, 2024

CollarChoke said:
Getting 0.271" on 0.003" neck tension here
View attachment 8524208
View attachment 8524209

Do you get that same measurement if you use the thinner part of the blade on the calipers out near the tips and measure dead center of the neck???

Sometimes when you use that real thick part of the caliper it hits an unsized portion of the neck down by the shoulder/neck junction or a bur if not chamfer/deburred up by the mouth. Just confirming thats all if the number changes...

Mike Casselton · Oct 14, 2024

padom said:
Whats your speed on that load? I run all 28" 6BR's but I run 106 A-Tips and they are absolute lasers to 1000yds.

Initially it was just over 2800. The closer the barrel got to the 5k mark it dropped to 2780.
A of now the barrel is very close to 5200 through it.
Lapua brass
Whichever SRP I grab. Usually CCI 400/450
31.0gr of CFE-223

I like simple

My 26" criterion runs pretty close to 2820, but it's only had about 2k through it.

The load is very mild, easy to clean and zero issues with temp changes.

padom · Oct 14, 2024

Mike Casselton said:
Initially it was just over 2800. The closer the barrel got to the 5k mark it dropped to 2780.
A of now the barrel is very close to 5200 through it.
Lapua brass
Whichever SRP I grab. Usually CCI 400/450
31.0gr of CFE-223

I like simple

My 26" criterion runs pretty close to 2820, but it's only had about 2k through it.

The load is very mild, easy to clean and zero issues with temp changes.

Damn that's fast for 112s in a 22" 6BR. I've shot probably 15-20 6BR barrels over the years and Im in that 2850- 2870 range consistently with mild 30.2gr Varget or 29.4gr H4895 loads out of 28" Bartlein and Kriegers with 0.105 and 0.110" freebore chambers

I'm also very suprised you don't have temp stability issues with CFE223. I tested CFE223 in 6ARC over the past few months and while it's advertised as having a 1.7fps per degree F temp change.. I tested it from 40F to 90F and I actually had a 2fps per degree change over that 50degree temp change..

For comparison, I tested the exact same load in the exact same gun on the same days side by side with AR Comp and across 50 degrees temp change I only saw a 6fps difference total from 40F to 90F ....

CFE223, BLC-2 and Lever are some of the most temp sensitive powders out there...

I found fast and very accurate CFE223 loads but when temps changed more than 15-20F I saw huge swings and accuracy changes

CollarChoke · Oct 14, 2024

padom said:
Do you get that same measurement if you use the thinner part of the blade on the calipers out near the tips and measure dead center of the neck???

Sometimes when you use that real thick part of the caliper it hits an unsized portion of the neck down by the shoulder/neck junction or a bur if not chamfer/deburred up by the mouth. Just confirming thats all if the number changes...

Dropped to 0.2700 using the tips on the center of the neck.

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