Chamber Choices for .223 Rem Bolt Gun

[voortya]

Hello All,

I'm in the process of getting started in bolt guns after shooting precision gas guns for a while, and was considering a .223 Rem to maintain some level of compatibility. My current plan is a Zermatt Origin action and prefit barrel, manufacturer to be decided. My initial thought was to go with a .223 Match chamber or .223AI if I was feeling adventurous. However, I have a large pile of 5.56 77Gr loads that I would like to be able to use in some way. Is there any chamber selection that satisfies the ability to use 80/90 gr bullets, but also tolerant of 5.56 loads and might allow the use of the pile of 5.56 brass I have. This will also be my transition into handloading, so I have no commitment to dies, etc. Thanks for the advice.

 

[RFutch]

Get at least a .090 freebore for the 80's .100 would prob be better. Also make sure you get a 1/7 twist or you will be limited to 80 and under.

 

[spife7980]

I bet your 556 ammo would work fine in a .090 freebore

My issue would be that its likely crimped primer brass and so I wouldnt want to bother with swaging or reaming. Id leave the 5.56 fodder for the ars

 

[voortya]

Thanks both for the advice. If I were to save the ammo for the gas guns, any opinion on stepping up to a more performant cartridge. My usage is primarily 1000 yds and in, so I had also considered something like 6mm BR. Not looking to spend a fortune on a cost per shot basis to encourage more frequent shooting.

 

[spife7980]

For pure cost savings the 223match/ai with a 75+ bullet in a 7 twist are fine choices if you are handloading anyways. After 600 things get sporty and fun but certainly not possible.

The br cases are great too though. If you wanted to be really competitive between 600-1k then the br would be a better choice among the two but everything about it will cost proportionally more as well.

 

[Greenmoustache]

I have a variety of cartridges I run in my Origin and TL3. I ended up getting my first .223 barrel about 9 months ago and just switched over to .223 AI. IMO I’d get the AI. It took it from a “nice practice barrel” to my round of choice for PRS matches <1,000yds. It’s essentially zero effort to get an extra ~150fps which makes a major difference with the 80gr and up. I got a “cheap” preferred barrel blanks prefit in 1:7 twist and the thing shoots lights out to 900yds. My current load is 26gr Shooters World Precision or Varget with Berger or Hornady 80s at 3,000fps and 5-6 SDs.

I was showing pressure with 24.5gr in the .223 Proof Prefit at ~2,850fps and SDs in the 15-16 range.

I wish I had gone AI to start as the incremental cost is essentially zero. I use Lapua brass for matches but have almost as good results with my LC range brass as long as I anneal before forming.

 

[voortya]

That definitely makes me lean toward the AI. Did you use any factory 223 through the AI chamber?

 

[nrspence]

I have a variety of cartridges I run in my Origin and TL3. I ended up getting my first .223 barrel about 9 months ago and just switched over to .223 AI. IMO I’d get the AI. It took it from a “nice practice barrel” to my round of choice for PRS matches <1,000yds. It’s essentially zero effort to get an extra ~150fps which makes a major difference with the 80gr and up. I got a “cheap” preferred barrel blanks prefit in 1:7 twist and the thing shoots lights out to 900yds. My current load is 26gr Shooters World Precision or Varget with Berger or Hornady 80s at 3,000fps and 5-6 SDs.

I was showing pressure with 24.5gr in the .223 Proof Prefit at ~2,850fps and SDs in the 15-16 range.

I wish I had gone AI to start as the incremental cost is essentially zero. I use Lapua brass for matches but have almost as good results with my LC range brass as long as I anneal before forming.

What freebore did you go with your 223 AI chamber?

 

[Greenmoustache]

That definitely makes me lean toward the AI. Did you use any factory 223 through the AI chamber?

Yep! I haven’t bought ammunition other than rimfire in years but I had a decent amount of factory loads with LC brass that I put through it. It shoots it as well as the .223 barrel I have but I wouldn’t ever choose to purchase factory match ammunition just because it would be a waste of money.

I did put a decent portion of my .223 reloads for long range shooting through it since that was my better brass as well. That way could still practice/shoot out to 800-900 yds just fine while fireforming.

 

[Nortex]

What freebore did you go with your 223 AI chamber?

150 is what I spec'd my reamer at and its solid with 80gr Vld.

 

[Gustav7]

I have a variety of cartridges I run in my Origin and TL3. I ended up getting my first .223 barrel about 9 months ago and just switched over to .223 AI. IMO I’d get the AI. It took it from a “nice practice barrel” to my round of choice for PRS matches <1,000yds. It’s essentially zero effort to get an extra ~150fps which makes a major difference with the 80gr and up. I got a “cheap” preferred barrel blanks prefit in 1:7 twist and the thing shoots lights out to 900yds. My current load is 26gr Shooters World Precision or Varget with Berger or Hornady 80s at 3,000fps and 5-6 SDs.

I was showing pressure with 24.5gr in the .223 Proof Prefit at ~2,850fps and SDs in the 15-16 range.

I wish I had gone AI to start as the incremental cost is essentially zero. I use Lapua brass for matches but have almost as good results with my LC range brass as long as I anneal before forming.

Another vote here for the 223AI. I have a Kelblys Atlas Tactical with a Proof steel barrel on it. I do not know the freebore. Really loving it so far. I took it to a Modern Day Sniper class where the range was only 700yds. It is within 0.2 mil elevation at 700 compared to my 6.5cm load, and mimics it to 500yds.

Running 80SMK's at 2980 behind some XBR8208. This load isn't amazing, but it performed great to 700 on steel. Unfortunately my barrel is 8 twist so i'm limited to 80 or less, but no biggie.

I just sucked it up and bought 300 lapua cases. Its a FUN gun that is pretty cheap to shoot as well.

 

[Greenmoustache]

Another vote here for the 223AI. I have a Kelblys Atlas Tactical with a Proof steel barrel on it. I do not know the freebore. Really loving it so far. I took it to a Modern Day Sniper class where the range was only 700yds. It is within 0.2 mil elevation at 700 compared to my 6.5cm load, and mimics it to 500yds.

Running 80SMK's at 2980 behind some XBR8208. This load isn't amazing, but it performed great to 700 on steel. Unfortunately my barrel is 8 twist so i'm limited to 80 or less, but no biggie.

I just sucked it up and bought 300 lapua cases. Its a FUN gun that is pretty cheap to shoot as well.

100% agree. I snagged 1,000 80.5 Bergers off someone here and they are lights out to 800yds. I originally was thinking it would be my “practice” load since I run 6 Dasher in competitions but I’ve been so impressed I might run it for my next competition in October. Almost identical drop out to 600 as my Dasher 105 hybrid load.

Luckily I got a 1:7 twist but I haven’t started to play around with anything over 80 yet.

 

[nrspence]

150 is what I spec'd my reamer at and its solid with 80gr Vld.

Are you fitting in accurate and mdt mags just fine or did you modify your mags. What I figured was a .100 freebore was about perfect.

 

[Nortex]

Are you fitting in accurate and mdt mags just fine or did you modify your mags. What I figured was a .100 freebore was about perfect.

Accurate mags is all I have ran besides the early crappy ai plastic mags. I do trim the lip for oal just on the front outside edge.

 

[Gustav7]

100% agree. I snagged 1,000 80.5 Bergers off someone here and they are lights out to 800yds. I originally was thinking it would be my “practice” load since I run 6 Dasher in competitions but I’ve been so impressed I might run it for my next competition in October. Almost identical drop out to 600 as my Dasher 105 hybrid load.

Luckily I got a 1:7 twist but I haven’t started to play around with anything over 80 yet.

God I’d love to run Bergers but I just have a hard time paying the same price for .224 bullets as I do for 6.5 bullets lol. They’re literally half the material.

Probably end up trying the 80 eld next after this batch of 80SMK

 

[Rob01]

.223 Wylde

 

[voortya]

Thanks for all the advice everyone, I think I'm going with a .223AI prefit from Preferred. They can do a .100 freebore, so I should be good to go.

 

[otnot]

If you ever want to shoot 90 gr the more freebore the better. PTG makes a reamer with .169 freebore. Here's a couple of articles:

F T/R Competition - 223 FTR Reamer and Freebore

I am new to the FTR scene and I am a bit unsure of what I should set my Freebore to be and if there is a specific reamer I should request. After googling a bit I am quite confused, I found a thread where two shooters mentioned they use a freebore of .169" and another said they use .212 and jump...

www.snipershide.com

https://www.dcra.ca/_files/ugd/b84a4b_ef0a3216eef349b19c9cb84235cefee5.pdf (Page 35)

 

[voortya]

I had actually read that thread. My understanding was that at that point, I'm basically limited to the 90gr bullets. I'd like to be able to shoot some cheaper factory/plinking loads for fire forming, and I don't think I'll be held back by the 80 gr choices

 

[Gustav7]

I had actually read that thread. My understanding was that at that point, I'm basically limited to the 90gr bullets. I'd like to be able to shoot some cheaper factory/plinking loads for fire forming, and I don't think I'll be held back by the 80 gr choices

That’s not really how that works. The longer the free bore the LESS limiting it is. The super short freebores are usually for someone running a shorter bullet(varminters), or something with a long ogive, So they can run close the lands and still be inside the case mouth reliably.
The longer freebore noted in the thread above is so you don’t have to push the 90/95 class inside the case more. It’s not some specific “only this bullet” number.

 

[voortya]

I was under the impression that at some point the jump to the lands became large enough with shorter bullets that it was unsafe/ineffective to use them. If not, it would seem that all chambers would use a longer freebore by default.

 

[nrspence]

That’s not really how that works. The longer the free bore the LESS limiting it is. The super short freebores are usually for someone running a shorter bullet(varminters), or something with a long ogive, So they can run close the lands and still be inside the case mouth reliably.
The longer freebore noted in the thread above is so you don’t have to push the 90/95 class inside the case more. It’s not some specific “only this bullet” number.

You have to take into account mag length. For example AR mags are going to severely limit how long you can seat out bullets so the standard 223 rem 5.56 223 wylde chambers are for AR mag length loaded cases. For bolt guns you have a lot more freedom with freebore and mag lengths.

 

[Gustav7]

You have to take into account mag length. For example AR mags are going to severely limit how long you can seat out bullets so the standard 223 rem 5.56 223 wylde chambers are for AR mag length loaded cases. For bolt guns you have a lot more freedom with freebore and mag lengths.

For sure, but we’re talking bolts guns here, and specifically 223AI.

I was under the impression that at some point the jump to the lands became large enough with shorter bullets that it was unsafe/ineffective to use them. If not, it would seem that all chambers would use a longer freebore by default.

Unsafe? No
Ineffective? No(depending on your definition)
Possibly less accurate because of too much jump? Sometimes, depends on the individual variables.

Scott Satterlee did some tests with jumping way out to 150+ thou without any accuracy problems, and I believe he actually found seating depth to be more forgiving out that far.

The reason you would get a different freebore is so that you can:
1.) Fit mag length (or some OAL goal) and still run closer to the lands
2.) Be able to run close to the lands with shorter bullets or longer ogive and still
Be seated in the case properly

The REASON you want the option to run close to the lands is in case your seating depth test shows you the best accuracy close to the lands, and/or sometimes the less the bullet travels in free space, the more accurate it can be, or the less deviation from accuracy you can see. This is, of course subjective and depends on your gun and load.

I suggest listening to the Internal Ballistics episode on the Hornady Podcast. Very good info on that.

 

[otnot]

My experience has been with my long throated barrel with a 1:7 twist, is that the 77 and 80 gr. bullets love it. Here is a example of of an 5 shots at 400 yards with 80 gr. Nosler. 80 gr. just doesn't preform as well at a 1000 as the 90 gr bullet does and since that is the distance I shoot the most that is what I set up for.

 

[Greasegun]

Does anyone know the freebore spec on a Proof .223 REM Prefit? Proof would not divulge that info on the phone.

 

[nrspence]

Does anyone know the freebore spec on a Proof .223 REM Prefit? Proof would not divulge that info on the phone.

I would bet saami spec unless it’s wylde chambering. Standard freebore is .025 wylde is .0619

 

[verdugo60]

I believe the PROOF pre-fits ship with a 223 Wylde chamber but not 100%. @LawnMM is having good luck with the ELD-M 80's in a Proof pre-fit, standard 223 chamber.

I just did a PROOF pre-fit for my Terminus Zeus and had my local smith Ackley-ize it, mainly because I don't want to have to trim. The extra speed with 88's will be nice too I suppose.

No speeds yet since my chrono battery died on my last range trip but Hornady 75 gr HPBT fireform loads in Lapua brass were 3/4 MOA or better with 23.2 grains of XBR 8208. Was tagging the KYL at 300 yards pretty easily down to the very small 2" target.

88 gr ELD-M with 23.8 and 24.1 grains XBR in fire-formed Lapua casings was too hot surprisingly, had heavy bolt lift and cratered primers. Seating bullets was pretty stiff, the cheap LEE AI die may have too much neck tension so I am now using a mandrel after resize and before seating to see if that lowers pressures at all. Also dropped the powder charge to 23.3 grains to try out. I'll likely need to anneal every few times too.

This is my practice barrel for my match gun and may be used for local 1 day matches sometimes so I just want a load that's around 1/2-3/4 moa with good SD's loading progressive style on my Dillon 550. Was working pretty good with my old barrel loaded the same way with a Preferred Barrel Blanks 223 AI on my Bighorn Origin.

 

[verdugo60]

Update:

23.6 grains XBR 8208 with 88 ELD-M, Lapua fire formed brass is doing 2800 fps in my PROOF 24” pre-fit, (Ackley’d).

Went 29/30 on a 1.3 moa plate at 550 yards from prone and kneeling. Load was “slop” loaded on the progressive, Dillon powder throw. ES of 50 fps, SD 17.

Best group at 100 yards was with TBAC Dominus, 5 shots.

 

[jLorenzo]

+1 for the .169. I shoot 75s,77s and 80s no problem. Longer coal allows for more powder. Working on the 88s too.

 

[Easy_E]

I would go with the Mack Bros action over the Origin if it were me . The Origin has some rearward slop that drives me nuts .
I built the same gun your describing Origin action 1 in 7 twist 223 match chamber in MDT chassis . Its been out to 1050 yards a couple times a real gas to shoot .

 

[nrspence]

I would go with the Mack Bros action over the Origin if it were me . The Origin has some rearward slop that drives me nuts .
I built the same gun your describing Origin action 1 in 7 twist 223 match chamber in MDT chassis . Its been out to 1050 yards a couple times a real gas to shoot .

That rearward slop drove me crazy as well. I sold mine and bought a BAT igniter action. I like the igniter a lot more.

 

[NFshooter150]

I had actually read that thread. My understanding was that at that point, I'm basically limited to the 90gr bullets. I'd like to be able to shoot some cheaper factory/plinking loads for fire forming, and I don't think I'll be held back by the 80 gr choices

Ya I kind of had the same thought process as you. I just recently swapped my mpa pmr pro 2 rifle 223 match barrel out to a brux mtu 26 and had a 223ai Manson reamer with .080 freebore made. It's a little short to run the 90s right now but once it erodes some more it will have enough freebore for it. It's been lights out with 77smk 80s and 85.5s even. The only thing to watch out for is the chamber will be much tighter so if you have loaded rounds of range pickups it might not fit if the die you used to size was like saami spec.. I made that mistake now I have 200 rounds I can pull or hand feed into an ar.