223 Projectile, High B.C., Short BTO?

[Lawnboi]

What powder are you running? Those are cooking! I just grabbed a 8lber of xbr to try after my varget supply runs out

 

[ericwh]

Varget.

I didn't have any pressure signs on the brass itself. Winchester primers are hard to read. Almost all are flat, even starting loads. I encountered the same thing on large rifle before I switched to 210m, which also seat better for me. Perhaps the seating is an issue. I am fed up with them but not a lot of options right now.

 

[Lawnboi]

Holy crap you must be very compressed with varget. That said I couldn’t reach pressure with the max I could squeeze in a case either. I stopped cramming at 24.6 or .8 can’t remember. Sitting on 24 grains right now on my 77tmk load, going 2750. 24 gets me a little crunch when seating around half the rounds, that’s after a few taps to settle and a drop tube for the powder.

Im already anxious for a rebarrel to a wylde chamber, hopefully I can grab a proof tikka blank cut it to 18” thread for suppressor. With 2.6” in the mag I think I could stuff a lot more powder in it the chamber will let me seat farther.

 

[ericwh]

With PMC Bronze brass (don't judge me) it's not actually that compressed. With the Sierras seated at the lengths I have them, there is more room in the case than with a 77gr SMK or similar bullets which are designed for AR-15 magazines. I would say the top of the boat tail is .015" below the neck shoulder junction. The Berger is slightly deeper in the case than the 80gr Sierra.

The Sierra Bolt Action Manual has 25.3gr Varget as max and 2900 fps in a 24" barrel.

Related to your TMK development, I like the Sierras but am considering going with the Berger since I'd like the option of shooting an animal with my target load. There is some data out there for people shooting deer with the Berger in .224 Valkyrie and having good bullet performance. The 80gr Sierra has the pointed or pinched tip and has the look like it might not expand.

 

[Lawnboi]

77 tmk are exactly what I’ll be shooting this year for deer, I know the normal match king is not known for being a good killer. If you shoot something with the Berger be sure to post it up. If I were hunting with the Berger I’d probably make well sure that the tip is clear and open.

 

[ericwh]

Lawnboi supplied me with some 75gr eld-m and also got some On SH. I was excited for these as they would give me good b.c. for range use, allow me to shoot PRS tactical division since they were under the 77 gr, and I was confident they would have good expansion on groundhogs with the polymer tip.

First round, powder testing. Shot some of the worst groups ever for this gun but also showed some that had promise. I went with 25.2 as it had good speed, lowest es/sd, and least vertical spread. These were all shot with .015 jump using my usual method of measuring the lands. Bipod, rear bag, suppressor.


Just finished a searing depth test at jumps of .020, .015, .010, and .005. Groups are circles. Really unimpressive. This was after I shot 2 sub-moa groups with 55gr v-max load developed for ar15 and before I shot a 1" 5 shot group with 80gr smk that had 4 shots inside .5"... while it seemed like group was better at .005" jump, the es and sd got progressively worse as I went from .020 to .005...



Sooo... I guess I will recheck my measurement to the lands and, if no mistakes were made, try bigger jump?

 

[ericwh]

Did a little reading and apparently the ELD-M like jump. I will try more jump in bigger increments...

 

[wind gypsy]

Did a little reading and apparently the ELD-M like jump. I will try more jump in bigger increments...

Eric, tagging in on this. It’s likely my new T3x lite has the same chamber spec as your CTR.

Put the first 25 rounds through mine yesterday with 8208xbr and 75elds. It shot at least as poorly as the 75s did for you but I had little confidence from the start because of the extreme seating pressure the virgin lapua brass required. Mine were seated at the lands at roughly 2.430” coal.

 

[ericwh]

Eric, tagging in on this. It’s likely my new T3x lite has the same chamber spec as your CTR.

Put the first 25 rounds through mine yesterday with 8208xbr and 75elds. It shot at least as poorly as the 75s did for you but I had little confidence from the start because of the extreme seating pressure the virgin lapua brass required. Mine were seated at the lands at roughly 2.430” coal.

I was measuring ~2.442 COAL touching lands so we're close. My methods aren't super consistent but I just use it as a base line anyway.

My original seating test was .005 - .020 jump (using my baseline).

I've now loaded up .028, .036, .044, and .052 which gets me back to book length of 2.390 COAL. Hopefully I find something in there.

 

[ericwh]

I downloaded Gordon's Reloading tool and been playing around with it. It says I'm only getting 92% powder burn with Varget in my 20" barrel...

At the top "node":
8208 XBR is 99% burn, and 90% case fill.
H4895 is 100% burn but very close, and 90% case fill.
N135 is 100% burn with a little bit of buffer, and 95% case fill.

So I think I'm going to look for N135. Maybe I can trade some Varget for it.

 

[wind gypsy]

I downloaded Gordon's Reloading tool and been playing around with it. It says I'm only getting 92% powder burn with Varget in my 20" barrel...

At the top "node":
8208 XBR is 99% burn, and 90% case fill.
H4895 is 100% burn but very close, and 90% case fill.
N135 is 100% burn with a little bit of buffer, and 95% case fill.

So I think I'm going to look for N135. Maybe I can trade some Varget for it.

What is the 8208 charge weight at the top node?

 

[ericwh]

I shot my second seating depth test today.

Average velocities were all between 2775 and 2805. SD between 10 and 13. ES between 19 and 28. No trend with seating depth.

~10mph gusts. Tried to manage it. 10mph should be about .2 mils for this at 100.

I am tempted to load 5 at .052" jump (book length). That seems to have 3 in a good group with 1 that seems to be an obvious outlier.

.028" also had me feeling hopeful - those were shot in a string from right to left.

.044" and .052" just seem sort of random bad groups.

I may load 5 at book length or just wait until I can find N135...

 

[wind gypsy]

Pretty tough. I think I might try the TMKs before giving the 75 ELDs much time.

Edit: Berger claims the 80 VLD and 85.5 LRHT work in an 8 twist.. probably not ideal but interesting.

 

[ericwh]

The 80.5 gr Bergers were looking real good at the charge that had the lowest SD/ES. I was not disappointed with the 80gr SMK either. If I was going above 77gr I would go with either of those. Probably the SMK for the BC.

I shot a powder test with the 77gr SMK and had 2 consecutive charge weights that were .375" (3 shot groups). Just not crazy about the BC for a gun that has no magazine COAL limitations.

I haven't shot the TMK but based on my experience with Sierras they would probably be my best bet at 77gr or under for combination of B.C. and accuracy. Plus I can kill stuff with them... maybe I will assimilate.

 

[ericwh]

Found some N135 to order yesterday and also read about the 77gr RDF for the first time.

I think the 77 grain RDF might be the best b.c. available at 77grains or less, that isn't an ELD?

 

[wind gypsy]

Found some N135 to order yesterday and also read about the 77gr RDF for the first time.

I think the 77 grain RDF might be the best b.c. available at 77grains or less, that isn't an ELD?

I've read a handful of comments from people struggling with consistency of the RDFs in various weights. Not the 77s though so I'd do some searching. Might be a good option!

 

[Lawnboi]

The 80.5 gr Bergers were looking real good at the charge that had the lowest SD/ES. I was not disappointed with the 80gr SMK either. If I was going above 77gr I would go with either of those. Probably the SMK for the BC.

I shot a powder test with the 77gr SMK and had 2 consecutive charge weights that were .375" (3 shot groups). Just not crazy about the BC for a gun that has no magazine COAL limitations.

I haven't shot the TMK but based on my experience with Sierras they would probably be my best bet at 77gr or under for combination of B.C. and accuracy. Plus I can kill stuff with them... maybe I will assimilate.

My tmk load is a one holer in my rifle, has decent BC and in the past have been somewhat easy to find. I wish they weren’t so expensive but they are an awesome bullet for both hunting and target. A little cross over in times like this is good.

I didn’t plan on shooting deer last year with the tmk, but it ended up happening when my hunting rifle had to go back to Hells canyon armory again. It worked so well I think I’ll be using it again in WI. Unreal performance.

 

[ericwh]

I shot some test loads (3 shot groups) with N135 today:

23.0 Avg = 2764, SD = 30, ES = 57
23.3 Avg = 2783, SD = 3, ES = 5
23.6 Avg = 2815, SD = 6, ES = 11
23.9 Avg = 2887, SD = 4, ES = 7
24.3 Avg = 2926, SD = 4, ES = 6 (Only 2 shots in this data, 1 failed to read).
24.5 Avg = 2960, SD = 17, ES = 34

I have been using Varget for all my .223 loads and have NEVER achieved SD/ES that low, especially over such a large range of powder weights. Very excited about that and going to try it with some less finicky bullets. Great velocity too.

Target with the 75 ELD-M was not so impressive again, but I did have one good group, which seems to suggest that there is a glimmer of hope somewhere, at some charge, with some seating depth.

These were all shot at ~ Hornady book length with ~ .050 jump.

 

[wind gypsy]

Shot the T3x lite 223 again today. Did OK with virgin lapua brass, xbr, and 77 TMKs. Did dogshit with the same but 75 ELDs.

The surprise of the day was when I decided to burn up some of my old 77 TMK AR rounds seated at AR mag length with varget and beat up LC brass that had seen a few firings in ARs.. bug hole.

 

[ericwh]

Its post hunting season winter so I'm back on this.

I shot a 5 round group of the 75 ELD-M with 23.3 gr N135 (most accurate and most consistent velocity from previous test.

And also a 5 rd group of 77 RDF with 22.2gr N135 (most accurate from initial test) and 22.5gr N135 (slightly less accurate but more consistent velocity).

The eld-m shot ok (~1") and had consistent velocity (SD of 11).

The RDF ith 22.2gr n135 shot better (~0.5" excluding the one that went way low - its velocity was ~150fps slower than all the others so I either screwed something up or there was a component issue). The accuracy results from my previous test with the 77gr RDF were confirmed.

For PRS out to 650 yards and shooting groundhogs as far as I can find them, I'm happy enough with the accuracy of this loading of the 75 eld-m. The velocity is more consistent and higher than the accurate loading of the RDF.

The RDF was easy to develop however and very accurate at 100 yards.