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AR15 with 90 grain berger at 2905 fps, impossible? Not so much.
- Thread starter Mod Adahy
- Start date
Brad, can you post a couple pics of the fired brass on some of the hot loads? It would be nice to see what the primers look like after firing.
Also, can you calculate how much energy is delivered at different distances out to 1000 yards with a couple different bullet weights?
Also, can you calculate how much energy is delivered at different distances out to 1000 yards with a couple different bullet weights?
I will look to see if I have any pics of the brass. I am sure I do somewhere.
90 grain smk @2880 fps with da of 6500 shows 465ft/lbs at 1k
77 nosler @3100 fps shows 231 ft/lbs at 1k
I've been playing Brads 5.68DMR the last few days and have to say that it's a very intriguing cartridge. The thing I like most about it so far is that the recoil is pretty much indistinguishable from a 223 Rem and that's with 90 SMK's. My 6mmART40 had a about twice the felt recoil and muzzle rise as this thing does, although to compare better it wasn't braked but was however a couple pounds heavier. So far a medium load only uses 26.2 grains of R-15 but still produces 2820 fps, no hint of primer flow or ejector smear at this speed and the primers aren't flattening yet. It looks like the brass can handle much more pressure.
Thinking ahead a little bit I bet this cartridge would be dandy for a low recoiling bolt gun with modified AI 223 mags and 90's throated out more. Hint hint, Brad.
Thinking ahead a little bit I bet this cartridge would be dandy for a low recoiling bolt gun with modified AI 223 mags and 90's throated out more. Hint hint, Brad.
I went out this morning to test velocity and see what speed the next barrel node up from 2820 fps would be. There was a tight node right at 2900-2910 fps. This test was another ladder test to see when I'd get pressure signs. 26.9gr (2893 fps), 27gr (2909 fps) and 27.1 gr (2910 fps) of R-15 gave very slight ejector smear, primers were not flattened, nor any smoke coming from around the primer. Those 3 shots went into 1.1" at 300Y.
Then I shot 25 rounds of the 2820 fps load to test for function and accuracy at 400Y, 590Y and 960Y. The vertical was small, 2.5" at 400Y and 4" at 590Y. The wind had kicked up by the time I got to 960Y which was 8-10 mph from 2-3 o'clock. My dope was perfect for 400Y and 590Y but was .2 mil low at 960Y???, maybe because of the extra wind, don't know. It took me 3 shots to figure out I was hitting low, then I was hitting left and right of my 15" plate using 1 to 1.6 mil of holdoff but hit it on the last shot.
Zero malfunctions so far.
I've got 25 pieces of virgin brass left to try so I'm going to load up 27 grains of R15 and see how it does.
In the future I'd like to try the 90 grain Berger VLD at .551 BC. IIRC a different reamer/throating than the one used in this barrel is needed. Sure wish Berger would make a 85-90 grain hybrid. It'd be perfect for this cartridge!
Is this the same as the 22 Lidahl Chucker Rimless that came out in the 40's with a 28 degree shoulder angle? Or is your reamer tweaked to different specs? The Chucker was a 25 or 30 Remington necked down to .224.
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One of the engineers in Army Ordnance Board suggested using the .25 Remington as a parent case for the SCHV Rifle back in the early 1960's, but the Whiz Kids shot him down. This is pretty sick.
The 75gr A-MAX at 3100fps would be brutal.
The 75gr A-MAX at 3100fps would be brutal.
Whats the difference in this chamber and the one black hole weaponry and a few others sell? I honestly didnt know there was so many people doing this but it makes perfect sense. Im just trying to figure out what exactly is different about yours over what the other guys are doing. Also I ran ballistics calcs and the 75gr amax is actual a couple tenths of a mil flatter than the 90gr berger and only gives up a tenth or two in the wind to the berger on a full value wind. So why shoot the bergers when theyre twice as expensive? The bergers would ring steel a little better at 1000 but thats about it.
Differences are in lead, shoulder angle, shoulder location and neck. We also are using premium blanks and GM or one of the other $90 blanks or hammer forgings.
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Out to around 500 you are right, a few tenths is all you save. Run them again and start comparing past the 500 mark, the windage on the 75gr falls off a cliff compared to the 90s. If you figure it at a 15mph full value wind, which seems to be the minimum every time they hold a shoot around here, you are looking at 3 mils vs 5 mils at 1000 which is a big difference. I know every shot isn't 1000 yards but when you are shooting across canyons and up the sides of hills the wind does some pretty crazy stuff so the higher weight and BC of the 90s will justify the extra cost all day long. If you are just shooting on a square flat range then you can probably get away with the 75s.
So what does that get me over theirs? I dont believe their barrels are hammer forged so that rules out the "cheapness" aspect and theyre reporting velocities close to what you are. At the end of the day I dont care how I get there if it shoots just as well and doesnt beat up brass worse over the same load in the other chamber. Just trying to figure out the difference in them.
The numbers I quoted are differences at 1000 with 3200 mv for the 75s and 2900 mv for the 90s. Sure the more wind speed you add the more the bergers are going to hold better. If youre shooting in 15mph full value wind youve chosen the wrong tool to begin with. At that point its time to step up to the big boy cartridges.
I am no engineer, but why can't someone make a bolt and barrel chambered for the 6mm Norma BR.? I do not know if the record still stands, but the 1000 yds. a five shot group was 1+7/8". My bolt gun will consistently shoot 1/2" and less for 5 shots at 200 yds with Berger 105 VLDs. The 1+3/4" target is at 400 yds.
Here is a picture of my best 200 yd. group and a picture of my .223 magazine with a 6mm Norma BR. with a Berger 90 gr. VLD in it. The 6mm Norma BR. is more accurate than the 6mm PPC past 300 yds.
Any comments?
PS: I use Lapua brass and no neck trim. Just load and shoot.
Here is a picture of my best 200 yd. group and a picture of my .223 magazine with a 6mm Norma BR. with a Berger 90 gr. VLD in it. The 6mm Norma BR. is more accurate than the 6mm PPC past 300 yds.
Any comments?
PS: I use Lapua brass and no neck trim. Just load and shoot.
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Too long for an ar15. 6CM in the AR10 is pretty much everything the norma is with cheaper brass and feeds great.
22Br has been done but not in the AR. Bolt would be too weak and hence the problem with the grendel bolt face. I agree that it would be the ideal cartridge in the AR 15 platform.
You are from Texas and I'm from Oklahoma, we both know wind is a everyday part of life and 10-15mph is the norm pretty much all the time. I was using 2900 and 3100, the 3200 speed is a way too close to the speed limit on matches, a couple of coupe of shots over and you get the big DQ. Yes something other than a .224 bullet will work better in the wind without a doubt but then if you go that way this whole thread is basically pointless.
Not noting the differences in the 75 vs 90. 5.56 harrison can not run the 90s anywhere near the same. 80's down are very similiar. I can not fathom they run a premium blank when they sell the entire barrel with extension for what a blank cost, unless they are getting a Kreiger for $90.
Yep it does seem like there is some form of wind almost all the time which is why I bought a 300wm to sling 208 amaxs at 2900fps on the really windy days. It bucks the wind great and costs almost half what a 338lm would to shoot. Hell even a 308 slinging 178 amaxs at 2650 is rough in the kind of wind youre talking. One of my next purchases will be a savage lrp in 6.5CM so I can shoot a lighter recoild round than my 300wm on windy days. The 300wm is just too brutal for long range sessions and the 308 isnt much good on the real windy days. Definitely a skill I need to work on myself. This cartridge wont be legal for a lot of matches and the ones it will be it will be extremely outgunned by the 6mm guns so this cartridge to me doesnt have practical match use. To me I see it as having the ability shoot cheapish bullets (75gr amaxs) while the bigger guns cool down at the long range firing line and for general long range plinking. So other than doing it "just because" the minimal gain in wind deflection on calmer days(<10mph) buys you next to nothing with the 90gr bergers and costs twice as much at the expensive of losing a tenth or two in elevation. For me I just dont see the point of the 90gr bergers. If the 80gr amax were available it might be the best bullet for this particular iteration of the 22x6.8.
I figured with how much you cited the lead on this reamer that that is whatbis allowing you to run the 90s faster than you would in other offerings. Just wonder what the point is of running the 90gr berger unless max wind deflection resistance is of upmost importance. I dont doubt youre using a higher quality barrel, my question was more about the functional difference IE the reamer with the longer lead. Should bode well for a little barrel life as well.
I need to look up the length of the 80gr amax and see if it would even work at mag length. Thats a long ass bullet but I cant imagine it being longer than the 90gr berger.
Biggest difference was in the shoulder although the lead played a part, it was just not as big a difference as the shoulder.
I am really considering this for a local club match or long range yote toy. I was shooting a 6.5cm surgeon which was a unbelievable rifle but at the end of the day I didn't have the time or extra funds to compete with the pros. The best part about this round is that it can be competitive enough to fill my needs and it will only cost my the amount it takes to build the upper since I already have a very nice long range lower built with my current 5.56.
The 12 LRP is a nice rifle and you will enjoy it.
The 12 LRP is a nice rifle and you will enjoy it.
Can't be to long as you can see under the 6mm Norma BR. is a .223 with a 62 grain bullet in the magazine. Here is a picture of a 6mm Norma BR. with a 90 grain Berger VLD with a .223 with a 65 grain Sierra Game King.
I do understand "now" that the bolt would be to thin for an AR15. I told you I wasn't an engineer. I guess in an AR10 you could use the 105 VLDs. By the way I don't think you lose much velocity compared to a .243, but you do get a more accurate round.
PS: What is a 6CM?
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Do you gwt any cracked necks due to setting the shoulder back for the longer bullet? Have you found the average limit of reloads on a piece of brass? Id imagine it ought to get 10 or so if the shoulder getting set back doesnt cause longevity problems.
Damn dude, maybe one day when I grow I'll get a surgeon too lol. Sounds like it fits your needs well and at the end of the day thats all that matters. I think this round will swrve my purposes well also.
Well I was talking about shooting the 105 berger vld. Otherwise I cant see you gaining much over this with lower BC lighter bullets, bolt problem aside. The 105 would be over the 2.3ish mag length available for the ar15 platform.
The 6CM is a 6.5 creedmoor necked down to 6mm. Shoots 105s very close to most match limita of 3200 while still having decent barrel life. Basically just another 6mm cartridge to add to the mix but ita shoulder geometry lends well to being in an autoloader.
My daughter just shot her DMR yesterday (although she does not know it is hers since her birthday is not until friday) with no muzzle brake and she loved it. Light on recoil. This will be one of her long range rigs. She will be 6 on friday.
I agree and hopefully I was not negative in answering your post, if I was it was not my intention and I would have been happy with the BR.
I have had no cracked necks or shoulders at all to this point. I have 9 pieces of brass that have 11 reloads on them at this point, I started with 10 and I chucked it because of loose primer pocket.
Sounds great. Now if lwrc would get more once fired brass in stock we would be good to go. Ive got two sons 4 months and 3 years that I hope to have out in the field with me in the next couple of years. Good for you getting your little out and shooting. I started early as well and strongly believe it taught me a lot of lessons that have many parallels in life in particular responsibility.
Last report on the 27 grain load. For some reason it turned out to be a little hotter than when I shot it a few days ago. The ejector smear got worse so I stopped shooting at 6 rounds. Still no smoked primers and the primers weren't flattened like you'd expect to see with a really hot load.
So with my particular 6 year old can of R-15 the 2820 fps load was the best load.
I will post the other powders in the next day or so. Just for an update, we have a Berger specific reamer coming. What we found a few weeks ago is that the SMK reamer shot the bergers ok but not great. The catch to the Berger reamer is that it will not do as well with the lighter bullets due to the COAL length being so short. The current reamer is a compromise between the SMK and Berger, it allows you to run the 75 grain and other light bullets at a COAL of 2.215" ish. With the Berger specific reamer they will be around 2.050". With the SMK reamer your COAL for the SMK is 2.296" and it jumps .025", another side note is that with the SMK reamer you can run the light bullets with any 6.8spc magazine and not limited to the PRI mag. The current LE reamer has the Barnes at 2.240" to also allow the use of any 6.8spc magazine.
Hopefully that all made sense and I will update as soon as I get the new Berger reamer. The SMK reamer is golden!!!
Hopefully that all made sense and I will update as soon as I get the new Berger reamer. The SMK reamer is golden!!!
No, I used a cardboard box and aimed at something on the box. That box is all shot up now.
I only shot two five shot groups at 100Y. 2.290" OACL length was .38", 2.285" OACL was 1.4" with one flyer.
I only shot two five shot groups at 100Y. 2.290" OACL length was .38", 2.285" OACL was 1.4" with one flyer.
Shot it again today with different powders or fine tuning powders. H4895 got to 25.6 grains before pressure at 2836 and 2842. ARComp got to 25.1 before pressure at 2867. N530 got to 25 before pressure at 2861,2836,2873. All those had groups at 300 yards around 5", that is with 6 or 7 different .3 grain differences in charge weight. Overlooked from prior powders was CFE. I had shot it before in ladder test with the bergers and 28.1 had .210 group at 300 @2886,2873,2879 so I thought about doing it with the SMK and the new Berger reamer. Berger reamer all fed from mag got 2923,2911,2917 and were around 2.2" at 300 in 3 shot ladder test. SMK reamer got 2866,2923,2904,2898,2892 at 28 grains from the mag and was about 2" flat at 300. So I loaded both and shot at 1075. Berger took .1 less in elevation and hard to tell a difference in the wind. All these last loaded came out good, primers nice, slight ejector swipe and primers came out of the brass with nice tension. I threw primers in those 20 to see if they had a change and they were all awesome. So they got deprimed and are in the tumbler. The only catch with the berger reamer is that any other bullet will be seated at 2.100 coal, that includes the 75 bergers. If loaded with the 75's, velocity is around 2980 instead of the 3070 because of the reduced case capacity. Also played around with CCI 41's and 450's. I was noticing a difference in charge weight with the 41, around .8 grains lighter to get same velocity and pressure. So they freed up case capacity, which is great. But apparently it is very dependent on which powder you are using. RE 15 was .8 less with the 41. CFE as .1 grain less to get same pressure and velocity. Hope some of that makes sense.
JFI, I know have over 1850 rounds through my 24" and I will upload a pic of a 300 yard group in a minute.
JFI, I know have over 1850 rounds through my 24" and I will upload a pic of a 300 yard group in a minute.
So far it looks like R-15 and CFE are the powders of choice. N540 and N140 might be too slow but worth trying.
How long is the barrel you have chambered with the 90 Berger reamer?
How long is the barrel you have chambered with the 90 Berger reamer?
23.5 for the berger barrel. N540 should be here today. Will try it on Wednesday with both SMK and Berger barrels. N530 is about 85% case capacity, which was cool except high node was way above comfortable pressure for me.
Here is the 300 group with the SMK barrel. Each square below is roughly 1/2". Elevation is pretty decent and I had the same wind hold. Wind was gusty from left to right at 6-15 mph.
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Just had a 22" carbon barrel open up with dies. It has been melonited on the bore and chamber. Threaded 1/2-28 and with rifle length gas system. It is a 7 twist and used the 90 grain SMK reamer and not the berger reamer, it will feed 90 smk and any of the lighter bullets. Also comes with 25 pieces of new brass. PM me if interested.
This barrel is .980 from the extension to the gas block, gas block is .936 and then .920 from there forward. Weighs almost 3.6# as it sits, so it is definitely a heavy barrel.
Changing the berger reamer one more time to try a shorter lead. Am happy with the current one but gotta try something to see if it improves.
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