I'm ordering a barrel for a precision gun and am trying to decide between these chambers. I will not be firing any factory 5.56 loads through it. Ammo will be almost exclusively handloads. However, I'm hoping to get some decent distance out of this build so I'm wanting my handloads to use 77 TMKs and probably loaded on the hot side. If it weren't for that, I would get the .223 chamber, but since I will be using hot loads, will that be safe? Or should I just go with the wylde? I feel like .223 would be slightly more accurate due to tighter chamber dimensions and shorter throat, but I don't want to sacrifice safety to get that accuracy.

Barrel will be a 7.7 twist Krieger.

Did the company chambering your barrel have a recommendation, or do they offer just the .223 or Wylde chambers?  Either way, I'd see what they recommend for your intended application.

Just looked at the TMK and the BC numbers look pretty shiny--comparable to the 80 grn MK but mag fed. Should make a great mid- to longish-range load.

You want the Wylde chamber period.

The Wylde chamber has the dimensions that a semi-auto requires for 100% reliability and the longer jump to the rifling your 77 grain bullets like.

Nowadays I wouldn't even purchase a .223 chamber for a bolt action. The rifling leade is twice as steep (3 degree) vs. Wylde/NATO 5.56 (1.5 degree) which causes pressure spikes.

Their are lots of other chambers that work well too. Noveske Mod 0, Compass Lake Engineering and 5.56mm match all come to mind. Good Luck.

Thanks, that's the way I was leaning. How does 5.56 match compare? Is that just a 5.56 chamber with a longer throat for 80 and 90 grain pills?

" will that be safe"

yes...  you will never blow up or damage a 223 bolt gun running 556 psi

If you are having Krieger chamber it then here are your options.

.223 REM Suitable from 44 to 77 grain bullets.
.223 WYLDE Suitable for US Spec and Commercial NATO ammo.
5.56 MATCH Suitable for bullets 80 grains and over loaded beyond magazine length.

That is straight from their website.

I just got a Compass Lake barrel. I don't remember there being a CLE chamber, just 223, 5.56 and Wylde, which I got.

I ended up getting the wylde. I have a Douglas from cle with their custom chamber. I really like it and was tempted to get the Krieger unchambered then sending to cle. But decided to let Krieger do all the work.

I just bought a 1:7.7 24" Krieger in .223 for my AR from Compass Lake and used their CLE chamber. You might find this interesting:
http://www.compasslake.com/images/Chamber.jpg

Chambering was finished out to a mirror finish. Also, they charge significantly less money than purchasing from Kreiger directly with a faster turn around.

The CLE has less freebore than the Wylde which is great for seating 80gr SMK's bullets, which is probably what you're doing if you want a 7.7 twist. My max coal is around 2.435" vs. the book value > 2.5". Compass lake's recommendation of 22.0gr to 23.2gr VV N135 was right on the money, although i blew a primer @ 22.9gr w/ Lapua brass (my lake city's case capacity are about 0.3gr greater than lapua). 22.0gr yielding fairly consistent 1"-1.5" groups @ 200 yards, I think i can get that a little better with some additional tuning.

Lighter bullets like a Hornady  A/Z/V-max seat around 2.230" COAL. Best group so far is a .494" @ 200 yards, rainy low 50's light wind.

-Bob

Thanks for that. Wouldn't having less freebore be more beneficial to lighter(shorter) bullets? I ask because I have a Douglas with the CLE chamber. It has no issues running up to max pressure with 69 SMK, but runs into pressure issues well before max with 77 grain pills. My thoughts for the reason for this is that there wasn't enough freebore with the longer bullets, causing a pressure spike.

Wylde chambers run 2.450" to 2.475" COAL when touching the lands with 80 grain Sierra Match Kings. Some NATO chambers can handle up to 2.550".

All of these chambers are much longer than SAAMI .223 and any of them will provide better overall performance when loading 68 to 80 grain bullets.

They shoot light bullets surprisingly well despite having longer freebore. Part of the reason for this is the gentle 1.5 degree angle of the lead and the other is the tighter .224" diameter (vs. .226" diameter on 5.56mm NATO) freebore. The free bore is just as tight as the barrel without any rifling in it.

You will get excellent results with a Wylde, CLE, Noveske Mod 0 or 5.56mm match chamber.

I agree you can't really go wrong with any of the above. I have a Wilson barrel from RRA and it has significantly more freebore than my Krieger barrel. The diagram i provided shows a JGS Wylde reamer spec which has 0.0369" more freebore.

Afaik, Less freebore just means you use a little less powder and results in a shorter COAL.  I use Quickload for load estimations and it's been pretty on the money (once i plug in my case capacity) for everything except Berger VLDs. With shorter bullets i'm seating really shallow, 2.22" or 2.21". With benchmark powder and lighter bullets i'm right in the accuracy node right before i start getting dangerous pressure signs. Same with VV N135 and 80gr SMK, accuracy node @ max velocity right before the pressure signs start showing.

Here's a chart showing some load data from a 50gr Z-Max w/ Benchmark that i just started working. I start by measuring shot groups with OnTarget and putting the data into a google sheet. The blue dots show the vertical offset from the point of aim to the shot group center. The red dots show the group size.  The lines are a polynomial plot of the dots.


This was done @200 yards with 10-15 mph winds which ruins some of the shot groups, but even so it's still possible to extrapolate data.