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IMR 8208 XBR and Hornady 68gBTHPs
- Thread starter RldrNewby
- Start date
I've had good luck with standard Hornady match bullets. 68 and 75s in 223 and 178s in 308.
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Well sir thats good but I have a couple of needs for tangent or hybrid applications.
1: 223 for several rifles same load. Different jump.
2: 308 bolt gun with a short magazine length.
No place for a secant ogive bullet in iether case for me anymore.
And in general not at all happy with hornady bullets performance in several calibers.
I am putting them at the bottom of my shopping list if at all.
1: 223 for several rifles same load. Different jump.
2: 308 bolt gun with a short magazine length.
No place for a secant ogive bullet in iether case for me anymore.
And in general not at all happy with hornady bullets performance in several calibers.
I am putting them at the bottom of my shopping list if at all.
Cant beat SMK but Lapua Scenars shoot great too and arent jump sensitive.. 308 and short magazine length is a match for SMK's
Update: I finally got enough brass in to work with. I went with Lapua (overkill but it’s done now). Headspace using my comparator was pretty consistent across all 200 pieces at 1.458” +/- 0.002 (most were +/- 0.001), but trim lengths were a tad more deviant. Did find two badly deformed case mouths. Uniformed all Primer Pockets, FL Resized without bumping the shoulders back as they were all just under where I like them to be anyway, then trimmed all to 1.750”.
I then revisited OCW test with 68g BTHPs, and also did as you recommend, and tried a Seating Depth Test with my 77g SMKs at 23.3g of 8208 XBR load. These were done round robin with 10min cool time between each flight. No Chrono this time. Forgot it
. Here’s what I got:Not sure what to do with the 68g load. POIs are moving around from starting left, to centering up, to ending right. 23.2 maybe then Seating Depth Test? Your thoughts are welcomed.
The 77g SMK Seating Depth test below was fun, but this was a first firing for the brass, and I’ll admit, it’s hard for me to break that many shots consistently, so I’m not sure if I was as precise as I should have been on my technique. Anyhow, my interpretation is that slightly over 2.250 COL at the 1.861 CBTO is looking good, but I’m all ears if you have any thoughts or recommendations.
Update: I finally got enough brass in to work with. I went with Lapua (overkill but it’s done now). Headspace using my comparator was pretty consistent across all 200 pieces at 1.458” +/- 0.002 (most were +/- 0.001), but trim lengths were a tad more deviant. Did find two badly deformed case mouths. Uniformed all Primer Pockets, FL Resized without bumping the shoulders back as they were all just under where I like them to be anyway, then trimmed all to 1.750”.
I then revisited OCW test with 68g BTHPs, and also did as you recommend, and tried a Seating Depth Test with my 77g SMKs at 23.3g of 8208 XBR load. These were done round robin with 10min cool time between each flight. No Chrono this time. Forgot it
Not sure what to do with the 68g load. POIs are moving around from starting left, to centering up, to ending right. 23.2 maybe then Seating Depth Test? Your thoughts are welcomed.
The 77g SMK Seating Depth test below was fun, but this was a first firing for the brass, and I’ll admit, it’s hard for me to break that many shots consistently, so I’m not sure if I was as precise as I should have been on my technique. Anyhow, my interpretation is that slightly over 2.250 COL at the 1.861 CBTO is looking good, but I’m all ears if you have any thoughts or recommendations.
I'm in a similar boat, shooting 77smk with IMR 8208, I chose 23.2grains. Neighboring nodes with similar POIs. Low ES and SD. Sorry, i didnt mark up the targets but i started shooting from the top left. The tightest targets seem to be seated 1.846, 1.843, and 1.828 CBTOs, so I loaded up 10 more of each and will test them out tomorrow. Tac didnt make the cut lol.
I was hoping to get touching holes like some folks, but that just doesnt seem possible to me any more. Looking at your results, our group sizes arent that far off, but your 1.836 & 1.861 CBTOs do look promising.
My original goal of 1/2 moa doesnt look possible, I will settle for 3/4 moa 10 shot groups now lol
Keep in mind guys, getting 1/2moa groups out of ANY gasser is not easy. While sometimes you can get lucky on components when building an AR, the recipe is a well built, properly tuned AR with a high quality custom match barrel (Bartlein, Kreiger, etc).
The other half is you, the indian....Everyone thinks they should be able to shoot tiny groups with an AR cause they do it with a bolt gun...completely different animal. Fundamentals and practice are key...good solid shooting position, square to the rifle, exaggerated mechanics of follow throw, trigger reset.... you have moving parts in a gasser. You can get away with poor Fundamentals with a bolt gun, but you find out real quick with an AR that's not the case. Even more magnified when you step up to a large frame gasser (308,6.5cm).
This is just info, not directed at anyone specific. I'm just saying, don't be hard on yourself. Don't always think it's the load....could be the barrel, you, the load, or a little bit of all of that... when you hear "I have a 0.5moa AR all day" on the internet 95% of the time its bullshit.....0.5moa is NOT easy out of an AR. Shooting a 0.5moa or smaller group is NOT a 0.5moa gun...
Just some thing to keep in mind when your setting expectations for your AR loads and what to look at and work on...
The other half is you, the indian....Everyone thinks they should be able to shoot tiny groups with an AR cause they do it with a bolt gun...completely different animal. Fundamentals and practice are key...good solid shooting position, square to the rifle, exaggerated mechanics of follow throw, trigger reset.... you have moving parts in a gasser. You can get away with poor Fundamentals with a bolt gun, but you find out real quick with an AR that's not the case. Even more magnified when you step up to a large frame gasser (308,6.5cm).
This is just info, not directed at anyone specific. I'm just saying, don't be hard on yourself. Don't always think it's the load....could be the barrel, you, the load, or a little bit of all of that... when you hear "I have a 0.5moa AR all day" on the internet 95% of the time its bullshit.....0.5moa is NOT easy out of an AR. Shooting a 0.5moa or smaller group is NOT a 0.5moa gun...
Just some thing to keep in mind when your setting expectations for your AR loads and what to look at and work on...
LOLOL, Its Round Robin, not Red Robin... funny stuff
It means, you DO NOT shoot 3 shots of the first charge weight and move to the next, and shoot those 3, etc. Thats not Round Robin.
Round Robin means you shoot 1 shot of the first charge, then move to the next target and shoot 1 shot of the next higher charge, then move to the 3rd target and shoot 1 round of the next higher charge and so on till you have fired exactly 1 shot of each charge weight in consecutive order from lowest charge weight to highest charge weight.... When your done, you go back to the lowest charge weight and you shoot it at the same target you shot that 1st shot at, then again shoot the 2nd round of the next charge weight and so on. Your firing 1 shot of each charge weight at a time.. Rinse and repeat till you have fired all shots of all charge weights, round robin style..
Today 3 groups at 300 yards to confirm 23.2gr imr8208 with 77smk 1.846" to ogive. Seems to be around 3/4-1 moa.
Maybe if I anneal the brass it will shrink the groups?
When measuring the bullet seating depth to the ogive with the Hornady tool, I usually measure 8 times while turning the cartridge. If I get 1.846 on all 3 sides of the cartridge, but 1 side I get 1.849, should I seat the bullet deeper until that 1 side measures 1.846, even if the 3 other sides.may measure 1.843?
Maybe if I anneal the brass it will shrink the groups?
When measuring the bullet seating depth to the ogive with the Hornady tool, I usually measure 8 times while turning the cartridge. If I get 1.846 on all 3 sides of the cartridge, but 1 side I get 1.849, should I seat the bullet deeper until that 1 side measures 1.846, even if the 3 other sides.may measure 1.843?
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No, annealing your brass is not going to shrink groups...thats not what annealing does...your measuring tools are not capable of accurately reading to the .001 consistently every time. Even thought your calipers may read to .001...pressure at which you apply, how you hold, etc...set your die to get you very close to 1.843 then load all your ammo..
Your getting 1moa @ 300yd....what more do you want out of that AR? Get a custom bartlein if you want any better but its not gonna be 0.5moa at 300yd....
Your getting 1moa @ 300yd....what more do you want out of that AR? Get a custom bartlein if you want any better but its not gonna be 0.5moa at 300yd....
8 times... damn. Personally I don't think you need to get that involved with it. IF you start chasing 1 thou here or 1 thou there after measuring multiple times on the same bullet you're gonna end up going in circles.
What I do is get my bullet seating depth to within 0.005 of my target depth, then I load 5-10 using the exact process I'll use to load all 300-500 or so, then measure each one of those for seating depth. I typically only measure the bullet (at the ogive) once, but if it looks a little cockeyed or I feel I don't have my calipers set consistently, then I'll turn the bullet and measure a 2nd time. Sometimes I adjust the die a bit, and sometimes I'm close enough that I'm good with it. Depends on what my seating depth test showed me. This last test, all the seating depths were pretty decent, with all tests coming in at sub-moa 5 shot groups.
If I do my part and my process is in sync, I'm usually seating to +/-0.001ish. I think my last run of 300 rounds, 90% of my rounds fell into a 0.003 window, so +/- 0.0015. The other 10% fell within a 0.004 window. Thats good enough for me, and after all they're getting ran in an AR, so I'm happy with that.
Been offline awhile and just now seeing your post. I think your rifle and loads are doing great. This stuff is fun. What I find fascinating about reloading is the opportunity to optimize whatever rifle platform you have to it’s fullest potential. I don’t think I have a 0.5moa gun, and I’m certainly not a 0.5moa technique guy behind the rifle, but I’ve seen some cool differences in what my rifle likes versus what it doesn’t like thru reloading. It’s an awesome feeling to go from only having a few very specific factory loads available to me (if they aren’t sold out or on Backorder
) that will shoot decent in my rifle, to having the option to tailor make an optimal reproducible round at home whenever I choose to. I also like the unknown in reloading in that you never know just how good you can get an average grade stock gasser shoot (in my case) until you try out a few things at the reloading bench. I went from shooting baseball & bigger sized groups with factory Fed XM193s to shooting consistently an inch an usually under with my reloads. That’s very comforting!I totally agree with everything you just said. To me, it’s all about optimizing what you have, and trying to get both the rifle, and the shooter as precise as both can get. It’s also about perspective and having realistic expectations. In my case, I wanted a 0.5moa gun, but I didn’t have the money to buy one. I also didn’t have knowledge or expertise to know how to build one, or the ability to consistently break the shots with proper technique required to be an all day 0.5moa shooter
. I’m trying and practicing hard to get there one day tho. I do enjoy shooting with a passion, and I’m learning more & more about this reloading stuff every day. It’s starting to click for me. I just reaped the benefits first hand of doing an OCW and Seating Depth Test. I didn’t understand what I was looking at the first time I did one, but now, after gaining a better understanding of what the tests are designed to show from your explanations, I got a more consistent load working than I ever would’ve gotten just picking best groups. Friday evening just before dark, I got a chance to push my 77gSMK load in development out to 500yds. I saw enough consistency there to try them at 1000yds. I know in theory the .223 is not really designed to shoot remarkably reliably beyond 600yds, but I figured wutha heck, I’ll try it, and was making hit after hit after hit with ridiculous ease at 1000yds. Groups at 1000 were not super impressive, but the fact that it hit the 3x3 plate with regularity was more that impressive to me. I never thought for a second my rifle was capable of doing that before the reloading OCW & Seating Depth tests. Thanks for your help!
I totally agree with everything you just said. To me, it’s all about optimizing what you have, and trying to get both the rifle, and the shooter as precise as both can get. It’s also about perspective and having realistic expectations. In my case, I wanted a 0.5moa gun, but I didn’t have the money to buy one. I also didn’t have knowledge or expertise to know how to build one, or the ability to consistently break the shots with proper technique required to be an all day 0.5moa shooter
There you go. Putting in the work with load development pays off. Especially when you walk that load out to distance. That's where you see guys loads fall apart that just picked tiny groups at 100yds...
I guess it goes without saying, but just for clarification, it was a 3ft by 3ft steel plate i was rattling at 1000yds, lol. If I could hit a 3x3” plate with my rig... I’d go buy a lottery ticket ASAP
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My load is pretty much the same as everyone else with the 77 SMk in my 18" Douglas barrel. 23.5 of 8208 and 1.850" to the ogive. I run .003" neck tension and anneal the brass. SD varies from 3-6fps. ES is usually 10-12. The groups vary slightly from .3-.8 MOA. I get the same numbers in my LC and Lapua brass which surprised me.
My upper and lower fit very tight but I still have to pull the grip towards me to get the groups to be a little more consistent. If I get lazy the groups open up. If I make sure to repeat how I grip the rifle they shrink back up. Play with changing your grip and see if it affects the way the rounds print.
Solid performance to 800 or so. I have pushed them to 850 but spotting misses is tough when I don't make a good wind call. I have not tried to push them further because they are going pretty slow at that point.
My upper and lower fit very tight but I still have to pull the grip towards me to get the groups to be a little more consistent. If I get lazy the groups open up. If I make sure to repeat how I grip the rifle they shrink back up. Play with changing your grip and see if it affects the way the rounds print.
Solid performance to 800 or so. I have pushed them to 850 but spotting misses is tough when I don't make a good wind call. I have not tried to push them further because they are going pretty slow at that point.
How do you like the Douglas barrel? I was looking at those and the WOA's for my next barrel... I just don't think I need or want to spend the cheddar on a Bartlein
I'm happy with it. I have some odd looking gas port erosion, almost looks like chunks missing or gouges, but it shoots fantastic. It prefers a little fouling to shoot really well. The best groups are in the .3's but it seems to be a solid half MOA capable barrel. It shoots the Federal 73 Berger factory load well and the Hornady 75 Match. The BH red box 5.56 77 shot about .75-1+" groups. I have shot maybe 100 rounds of factory ammo through it. The rest have been my hand loads with Sierra 77 or Hornady 75 which it shoots equally well. I can't have a suppressor here in CA so I can't comment on it shooting suppressed.
Mine came through Centurion arms years ago when he was still in CA and a relatively new brand for the AR market. He claims the chamber is "optimized for MK262" 5.56mm. I have no idea if there have been any changes to their barrels or chamber in recent years. I know the WOA have a great reputation and to be honest, once this thing is shot out I will probably replace with one of their barrels. In the end it's an AR with a regular forged upper and lower. I can only expect so much from it without going to something like a JP for example. I will also probably change to a 20" to get some extra velocity too. My current loads run 2670. I have pushed them faster but lost accuracy. I went to an adjustable gas block and all it did was eliminate some of the ejector swipes I would get here and there.
I am very happy with Bartlein in my bolt action rifles. I wouldn't mind trying one of their barrels in my AR. I might build a 6ARC next year and I will run a Bartlein for that build more than likely.
Interesting update on my developing loads. 68gBTHP seems fine. Shoots lights out at 100yds and 500yds, but have only tried a few shots at 1000yds with it, and i got a couple hits at 52MOA and stopped. At home with better lighting, I saw ejector swipes in my 77g SMK load in development on about 1/4 of my brass at 23.1g of 8208 set at 1.861 CBTO. I’m shooting consistently around 3/4” groups & under at 100yds at 23.1g with this load, and hammering steel at 1000yds at 48MOA (Only a 16” Barrel). My initial OCW was done with mixed head stamp LC, and folks tried to tell me that Lapua Brass was overkill for an AR, but that’s all I could find at the time without tapping resources that I didn’t wanna trouble at the time. My question is this. I’ve heard Lapua has a smaller case volume than LC, and since my Unfired Lapua measured 1.458 to headspace datum line, and 1.464 to the headspace datum line Fired, could the excess headspace in Unfired Lapua (plus the smaller case volume as compared to LC) be responsible for the ejector swipes at 23.1g IMR 8208 XBR with 77g SMKs? That seems to be a fairly safe load when I research what others are loading. My second question is if I reduce by 0.2g, will I need to redo my seating depth test?
Isn't the Lapua brass 223? The LC is 5.56, hence the higher pressure its able to tolerate.
I’m not sure. The box says “.223 (5.56 x 45mm)”, so I assumed it was rated for 5.56 NATO pressures. Hoping it’s just a one off combination of new brass that has a smaller case capacity, which is also .006” shorter than my chamber headspace that is creating a false positive sign of pressure. I’m thinking smaller volume cases will have greater pressure with an equal sized charge in a higher volume case like LC, and being .006” short of chamber headspace, I’m guessing the case is slamMing back into bolt face a bit aggressively. I will probably just back off 0.2g, repeat my seating depth test, and if no pressure signs, just pick the best group, and go from there. I’ve already resized the cases, and now they are at 1.462 give or take a thou, where when fired, they read 1.464. Hopefully my theory and plan will work out.
To my knowledge, brass is brass. The alloy that LC is made of may be slightly different, but I've never heard of any brass manufacturer having stronger brass than Lapua. Maybe just as strong. Its not like Lapua's brass is only rated to SAAMI pressures but LC is somehow rated higher. Guys using Lapua brass in bolt guns are running loads over book max (over NATO max) and Lapua continues to deliver longer life than other brass manufacturers.
The difference in SAAMI vs NATO pressures for 5.56 has to do the with the chamber of the rifle. A .223Rem chamber is spec'd to SAAMI pressures(~55k psi), an AR15 with a 5.56 nato chamber is spec'd to NATO pressures (~62-65k psi).
The smaller case volume could account for higher pressures, and therefore ejector swipes. Keep in mind, Lapua is great brass, and to have the life that Lapua brass has, its generally thicker...and since the outside dimension must remain the same, you lose volume on the inside. If you ticked the load back 0.1 or 0.2gr you may find you reduce that pressure and keep your original velocity from the LC brass load.
From what I've learned on here, less headspace actually reduces your pressure (counter intuitive). This is because more energy is required to expand the smaller brass, which results in less energy given towards the bullet and chamber, resulting is slightly lower pressure.
My guess is, the smaller volume of the Lapua Brass has driven up pressure a bit. I would reduce to 22.8-23.0gr and try it again over a chrono and watch for pressure signs
The counter intuitive part made my head spin at first, but I totally get what you are saying. Thanks for explaining that. Yessir, gonna tone it back 0.2g and recheck. With any luck, my velocities will still be comparable as I really liked the way it shot.
Fired 20 rounds of 77gr smk at the 600 yards today. 2 shots went off the paper. Didn't hold over for cold bore, left 0.2 mils. Wind hold was about 0.3 mils right, I can see that now. My ballistic calc app had me low 0.2 mils.
Brought the wrong battery cable with the Chrono and was not able to get velocities. I wonder what caused the 2 high and 1 low.
Maybe it's time to clean the gun? Bore and upper hasn't been cleaned in ~900 rounds.
Brought the wrong battery cable with the Chrono and was not able to get velocities. I wonder what caused the 2 high and 1 low.
Maybe it's time to clean the gun? Bore and upper hasn't been cleaned in ~900 rounds.
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What was wind? Around 15mph?
Im curious how your app had you 2 whole mils low? What info did you input? Lol... that’s like a little less than half your total vertical adjustment
Awesome that you were on paper right out of gate at 600. Tells me your app and data are close. Hard to say what to do next without the velocity data. In my limited experience, I’ve tweaked the MV in my app when off paper to true it up. Sometimes I’ll play with the BC when it’s true at one distance, bit it doesn’t hold up farther out. Maybe try slowIng it down in the app 40-60fps, and see if the slow down will add 0.2mils to the required hold?
Edit: My apologies. I misunderstood the original question. Read it too fast, & thought you were referring to the 0.2mil low. After looking more closely at the Target, if the squares are 3” across, the bulk of your vertical dispersion seems to be around 6” or close to 1MOA at 600yds. The high and low shots could’ve been anything from changing conditions to rest/shot break to load related inconsistency. Hard to say. That looked plenty impressive to me.
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Thanks. I agree with your conclusions. Today I tried some 10 shot groups at 100yards to really dial in my technique. With 10 rounds left, I decided to dry fire and noticed the gun moves up to 0.2 mils when the hammer hit the firing pin. So then I started gripping the sides of the stock wfirmly wth my support hand to keep it from moving side to side and fired my.last 10 rounds. The group
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