23.0 - 23.5 H4895. And 24gr of Varget or RL-15 are standard service rifle loads in CMP or NRA Highpower. If your using a Wylde, NATO, CLE or other match type. 223/5.56mm chamber you will be fine. A common practice among highpower guys is to trim the spring for the ejector, this will make the brass stay in a nice neat pile close to you and also will limit the damage to the brass caused by the ejector. Off the shelf Bolts have very tight ejector springs that will Marr brass with even light loads.

It’s Thanksgiving but it feels like Christmas because there’s a new mk262 clone video to watch!!!

My vote is for the same test over again at less charge weight. I think reloader 15 is showing excellent accuracy (understanding that it didn't hit the velocity Mark). Also have very high hopes for h4895 as it is always a great performer for me in almost all weights of 223. I think it would also be a good idea to consider a standard primer given the pressure signs so early..... Maybe federal AR match or Remington 7.5s.

This video is just as important as the others, it shows the signs that one should look for when pushing the limits too far and when to stop.

I posted this a few vids ago.. I think you need a faster powder. You are shooting a DI gun which is bleeding off 100-150fps down the gas system. You don’t get a true 18” barrel burn like you would in a bolt gun. You need to get most of your burn before the gas port. Not all but most. If you run you data again for 16”the 2”barrel length should comp for the gas system billed off. But you need a powder that somewhere around 90-95% burn at 16” so you gain back the velocity in the last two inches. Simple way to test what I’m saying.. throw your loads into a carbine gas system riffle or a bolt gun and compare data. Your bolt is getting really really dirty for very few shots which means you have way way too much unturned powder coming back. You need a slightly faster burning powder.. This is why you were so surprised to see ball powder not extruded when you opened the case of the black hills.. they went ball cause it’s faster burning powder..

Thank you for the great series on the MK262 load development. Very informative as are all your vids. This is where I tell people to go to learn how to load.

Hey man, appreciate you sharing both successes and failures. Very important for us here to learn to see both sides of reloading. Its never fun to admit slight errors, but we really appreciate it and respect you more for it. It will help us all from blowing our faces off! Best reloading channel in history, keep it up!

I believe that a few other commenters have nailed down why there is an issue with pressure, starting with... components, OAL and possibly rate of twist combined!!! But we are all (most likely) guilty of not following the published data. We are all more than conquerors but we learn here to never under estimate. Great job of putting on the breaks. Well done

Happy Thanksgiving. I have just started reloading .223 and am thankful for this video series. Have a great day

Happy thanksgiving and happy reloading.

Funny I just saw this now. I use the 77smk with both R-15 and h4895 for CMP service rifle loads. Using 24gr H4895 and 24.2 R-15. Both hold the same accuracy, about 1" at 200 yards. 20" heavy match service rifle barrel, Wylde chamber, 7 twist, average coal 2.250-2.260. Don't remember the velocity, somewhere in the low to mid 2700's. Pretty much a standard service rifle load. The R-15 load will flatten a primer every once in a while in the summer time, even use the same charge for 80gr bergers.

Happy Thanksgiving! I was so excited to sit down and watch this video after the deer didn't show this morning and then so disappointed when these powders didn't show well. They are two I have on hand and I really like RL15 for the good accuracy, but it will never win the velocity race as your result show. Results not withstanding still a great video. Keep up the good work!

Happy Thanksgiving JRB and to the rest of us who watch. With any bad, there can be good. Sometimes the trick or problem is just trying to figure out what the “good” part- although, this one is pretty easy. While it may have been a “dumpster fire” for you, it was a stark reminder for us, certainly me, all to not get overly confident, maybe even lackadaisical, with the reloading process. Great vid, sir! Have a happy holiday.

Wow, I am bummed! I just picked up several hundred 77gr bullets and was totally fixing to use RL-15 in LC brass since I have a couple of pounds of it. Your series has been of immense value and it looks like my plans will be changing. For all my other 5.56NATO loadings in Hornady bulk 55gr FMJ, Nosler 55gr BTV(Varmageddon), Sierra 69gr SMK & Nosler 69gr HPBT(Custom Comps) my go to powders have always been IMR4895 & RL-15 with never an issue. Thanks much for all you do for all us reloaders.

To Johnny & to the rest of the JRB family: Happy Thanksgiving everyone!

Good rule of thumb is to start 10 percent below starting charge and ladder up. Yes you were very lucky!

Sierra uses different brass, primers, and OAL. Could be the tolerance of all 3 stacking up to give you the over pressure.

Reload books data from 223 brass. LC is 5.56 brass, the capacity difference is significant. Best reloading videos out there!

My favorite part is watching u shoot the groups

happy thanksgiving and I am glad you still have a face. If anything you have demonstrated that IMR 4895 and H4895 are definitely not interchangeable. When you do try it again I think you should use Hodgdon max of 22.6 and work up to it in .3 grain increments. hopefully it will still get close to the performance you are looking for and be safe.

Lake City brass has a little less powder capacity = higher pressures are possible.

Lake City brass is less capacity than Winchester brass (Not to be confused with WMA Winchester Mil Spec Brass), your C.O.A.L. is a major contributor (Spec calls for 2.260" coal), and your barrel twist rate is less than 1:12", any twists less than 1:12" will increase pressure. Chamber Free Bore and Lead in 223 Remington is shorter than 5.56 Wilde, Wilde is shorter than 5.56. If you load for 223 Remington then Wilde and 5.56 will have no problems, but not the other way around= If you load for 5.56 and shoot through a 223 Remington barrel you will blow your face off. Reduce your load 10% with LC brass and #41 primer and work up in 1/10 grain increments. Try Benchmark instead of H4895 it is faster burning and with compressed load under the 77g sierra will develop less pressure and should get you to 2750fps.

Thank you for ALL YOUR GREAT VIDEO'S....

Happy Thanksgiving Everyone. Glad you didn't blow your face off Johnny.

Hey there. I just found your channel recently. I really like your channel. Now, I have done this very load. I used starline brass for the overall tests, but i also loaded some lake city brass and found that with these loads the lake city all showed pressure signs. I loaded them all to 2.250 which was my mag length. That gave me 0.015 jump in the rifle. I had used the lake city brass for my sighters and warm up. I was a idiot and didnt look closely enough at those until after returning home. The 223 starline brass didnt show hardly any pressure signs until the last 5 shot group. No ejector swipes but a slight flattening of the primers. I dont own a chronograph yet so I dont know the speeds. So with my data somewhat compared to yours I would say that the reason for your pressure sign was the brass. CCI BR4 was my primer. Just thought that i would share that.

I do love this series....

I run 23gr of R15 with the 77gr Sierra Matchking. Awesome groups!!

Miss your videos man. No matter what they are about.

Johnny, it comes down to how forgiving each powder performs. Think of it this way, some of the powder is like taking .20 cal metal rod with 3 inches of .20 rubber on the end and then hitting the metal rod with a sledge hammer to drive the bullet down the barrel. Other powders are the same but no rubber at the end of the metal rod but hitting the rod with the same amount of force. Some powder are more forgiving when closing in on max pressure. You have already demonstrated some of the forgiving powders and now you found H4895 is not forgiving at all. I would also suggest to check you powder dispenser to see if there is some old powder clogged up somewhere.

I shot up to 24.5 grains rl15 with hornady 75 hpbt before seeing those pressure signs in a 20 inch barrel, offered real good accuracy too.

I'm supriesd that the Hodgdon data for the 77 grain projectile is for a 1:12" twist. That's way too slow for the 77. Your faster twist rate may have increased pressures as well. Happy Turkey Day!

Try adding a adjustable gas block to your DI rifle and lower the gas pressure to the bolt I had a AR that would do ejector swipes/smears/marks on some factory loads as well with hand loads with h4895 but I added a adjustable gas block and notched down the pressure and it solved my issue with it it also you could try this load in a bolt gun and see if you still have pressure signs this is a way to see if is indeed a over gassing issue or a legitimately a hot load. Great content BYW enjoy seeing it.

YEAH WHAT HE SAID!!! Hey man, appreciate you sharing both successes and failures. Very important for us here to learn to see both sides of reloading. Its never fun to admit slight errors, but we really appreciate it and respect you more for it. It will help us all from blowing our faces off! Best reloading channel in history, keep it up! YEAH WHAT HE SAID ALSO!!!! My vote is for the same test over again with revised charge weights. I think Reloader 15 is showing excellent accuracy (understanding that it didn't hit the velocity Mark). Also have very high hopes for H4895 as it is always a great performer for me in almost all weights of 223. I think it would also be a good idea to consider a standard primer given the pressure signs so early..... Maybe Remington 7.5s. CURIOSITY YA KNOW, PLUS UNFINNISHED BIZZ ,

I know this is year's past, but great video. My Stag model 6, Stag’s earliest version, fires a 77gr SMK most accurately at only 23.2 of RE15. Vel was in the 2600’s. My favorite load is 60gr Vmax over 25.2gr Varget for this rifle.

Awesome Video, love this series. groups were looking strong if it was not for the ejection/extractor marks. Can't wait for your 6.5CM videos and your Custom PRS build down the line. Oh and I hope you can try the 6.5CM Brass from Lapua. Keep the Great Work up. Best Reloader on KZfaq.

Happy thanksgiving brother!

What up Johnny! Can't be all great all the time right. Keeps you on your toes! Glad that you're safe man. I hear you speak about how great Berger bullets are so I just got some 73 grain target bullets. No KZfaq love for the Bergers? Trying to find some load data but not much out there. Maybe I'll split the charge between the 69 and 77 SMK's. Keep up the great videos!

My experience with 24.5 grains of RE-15 under the 77 in Winchester Brass primed with Winchester Primers delivers 2750 fps and is sub MOA with irons from sling supported prone position. I shoot it at the 200 and 300 yard line. The loading works nicely using an MOA wind constant of 10 at 300 yards. Douglas button rifled bbl smithed by CLE with CLE .223 chamber, 1/7 twist. My last EIC match I shot poorly but I was one of only two shooters to get wind direction and velocity right at 300 yards. 37 shooters put opposite wind on their sight and were about 6 MOA off mark, that’s 18 inches off, meaning hits in the 5 ring or worse . At any rate that helped me get back into the match and although I only finished with 474 X 14 it was good for second place and 8 leg points, 4 points more than needed to go Distinguished.

Happy thanksgiving JRB! Glad to see you post these videos. Showing people that reloading doesn't always work the way you think its going to is important. It's not always rainbows and lolipops.

It was that attempt at humor that was your demise.

Happy Thanksgiving Bro. Hope you have a peaceful time with family and friends today. Maybe get some sleep after dinner in a lazy boy. Well, I know it does not have anything to do with your tests, However, I found it pertinent to say, Many High Power service rifle guys shoot the 68-69 grain bullets up to the 300-yard line, at the 600-yard line slow fire they do over pressure their brass and just write it off as the cost of doing business with the 75-77 grain bullets and those two powders(Accuracy IS Outstanding). However, You are doing it right and stopping at signs of overpressure. The 5.56 or .223 was never intended to be able to handle the pressures that are generated in that weight range of bullet, powder selection you are using and the Velocity you are trying to achieve. Stopping is good progress if a dangerous situation is apparent. Good Video Bro, Dave.

Using a Windham 20" profile barrel, 24.5gr RL-15, Nosler 77gr HPBT bullet, CCI SP, LC Brass, OAL: 2.255", my average velocity was 2678. I did not notice any pressure signs to speak of. I am puzzled with your results. On the other hand, manufacturers tinker with the formulations used in their products which alters the results. Regardless, excellent video! When I finish my current 7.62x51 reloading project, I am going to work up some more loads for WOA 20" barrel. This barrel allows me to consistently shoot sub MOA groups with Hornady 75gr BTHP and 24.3 RL-15. This WOA barrel shoots excellent groups with Nosler 77gr, Sierra 77gr, and Hornady 75gr bullets.

Hope this helps 😉 Case: Lapua .223 Match Powder: AR-Comp, 23.4 gr Primer: Federal 205MAR Bullet: SMK 77g can FPS: 2750,2757,2751,2761,2749 FPS Average: 2753 STDEV: 5.18 .600 MOA, 100 Yards

I had a similar experience with H4895 and pressure signs at surprisingly low charge weights, I was very surprised considering it is an extruded powder.

Man I really thought today might be the day.....you blew your face off!

Happy Thanksgiving

I love reloader 15 it’s a complete rockstar in my 308.

your OAL was 2.246, both of these powders use 2.26. hence the pressure signs. I would like to see these same charge weights but with an OAL of 2.26. should be much better. keep em coming johnny!

BTW, I know guys who run 25gr R-15 with no pressure signs, all depends on your chamber I guess. I get no pressure signs running 24gr H4895 and have been doing so for years, even used this loaad with starline 5.56 brass, which has less capacity than LC. Mike your case heads, and check for excessive case head junction buldge.

Gotta hand it to ya....you got some brass cahones!....pushing the envelope on those max loads!

H4895 is a wonderful powder but it can create some pressure quickly. It can create some superb loads .1 grain at a time. I've only found it practical for 55 to 60 grain pills. Running 25g with non tipped varmegedon 55 grain non tipped around 2.250 plus or minus 3 tenths of a grain I can regularly get under .5 moa in an 18 inch barrel. I have had some of the same results with higher grain bullets. Ide love to see what the 55g bob's do with h4895

I don't think you made a mistake in charge weight here Johnny, It must be shortened COAL, dirty barrel or bad brass causing these early high pressure signs. I've noticed with my own load developement that it is very important to start with a clean barrel for each bullet I intend to shoot. As it greatly affects the accuracy of that bullet with foreign copper in the barrel. This is just the characteristics of my rifle yours may differ as I regularly see you shoot 2 and more bullets simultaneously in the one session. It just goes to show you that every barrel is different. H4895 is my favourite powder in .223 REM so please do not give up on it just yet. Great video's on your channel and you always put a lot of effort into them. Also love the way you don't edit your mistakes! Makes me feel not so stupid for making mine. Any chance on a subsonic 77gr SMK video? I really enjoyed the last one. Thanks

Thanks a ton safety first

When I first started shooting 300 BLK, Hornady VMax factory ammo gave me pressure signs. It was the buffer. The load you are trying to clone is for Military M4s, which have a heavy buffer standard, shorter barrels, and no suppressor. Buy some factory versions of the ammo, and see what you get (without the suppressor, just in case). Oh and TURKEY!

As you stated from the forums, I would bet that 24.0 grains of RL15, at magazine length, would be an extremely good shooting round.

Happy Thanksgiving! For grins, you could probably double check head space with a go /nogo. No blowing up faces during the holidays. It's not fun explaining the family photos. BTW which 262 load is in the performance lead?

This is crazy I had a similar issue yesterday with the hodgdon website telling me that 26gr H4895 was Max for the 69gr SMK so I started at 25.4 I had crazy pressure sighs. Flat primer and a bad ejector swip. Now on the other hand my load with 77 gr Berger's run 2795 with 23.8 gr H4895 out of a 20 inch Wilson combat Super sniper and it shots lights out with almost no pressure sighs.

IMR 4895 and H4895 usually have a difference of about 1 gr of powder (H4895 lower of the two).

Do you think the shorter OAL you're using vs. the Hodgdon data could have caused that much of a pressure difference with H4895?

Great Series you've made. It's interesting to see how the differences in the various powders perform. Given that the Black Hills powder is not obtainable to the general public. What do you feel is more important, obtaining the velocity and group size of Mk262 Mod 1 or obtaining a load that will out perform the accuracy of Mk262? Some of the groups you've shown have been sub minute of angle which would make most people extremely happy. Keep up the good work! Happy Thanksgiving.

Never was one to reload for the .223/5.56 because it never really interested me. After looking into to those 77 SMKs, I have a few boxes of projectiles and a couple pounds of RL15 and TAC to begin to tinker with.

15:09 that piece of brass ejected into the next county

My favorite load in a 20" BCM is 23.2 gr of H4895 at 2.255 and nosler 77gr custom competitions. I get about 2750 fps and shoots about .6" consistently when I shoot straight. Would love to see another work up in H4895 with 77s

you can adjust the gas system to help with ejector marks

13 seconds in and i think ur gonna c some good groups today.

Have you tried IMR 4198? I use it for my 55gr fmj reloads using 19.6 - 19.8 grains never had a problem with them and are pretty accurate

The sierra data was at 2.26” COAL, so the 2.24 length is perhaps the reason for your pressure

Hodgdon H4895 - Tried this powder behind the Sierra 69TMK, had pressure issues before either Hodgdon’s or Sierra’s max load data reached. First (and hopefully last time) ever had at primer blow. I moved on to CFE223 for both 69TMK & 77TMK loads, great for pressure control, velocity, and case capacity, however saw the same thing happen to Johnny as what I suspected was happening to me. Somewhere around 2700fps the groups are gone. Perusing my luck now with PowerPro 2000-MR, with many thanks to Johnny for the MK262 Series, else I probably would have missed this powder. I may also look at PowerPro Varmint, anyone’s thoughts on this?

TAC and IMR 8208 is what you need to duplicate MK 262. I prefer IMR 8208 with 77 MK

To be fair, there is no expectation that the new BCG would react the same to pressure as the old BCG. You changed powders and BCG at once. Maybe try the new BCG with the old loads and see if they mark up the brass. Was the gas also turned back down after cleaning?

According to the burn rate chart I have shows H4895 as a fast burning powder and I'm surprised they even recommend it with that heavy of a bullet. Between the 556 brass having less capacity and the magnum strength primers I wonder if that combination is spiking pressure which leaves you with little room for error with that powder.

For comparison, I run 80 SMK's over 24.5 grains RL15 out of a 20" WOA barrel with Wylde chamber...somewhat similar to your setup. My fired LC brass has roughly the same headspace as yours, I think WOA cuts a very consistent chamber. My standard load is hotter than your beginning loads. I chrono ~2750 fps with the heavier 80 SMK's and my brass shows definite ejector swipes. Your results are very surprising. Lots of people choose RL15 (& Varget) because you can literally pack the case full, seat a bullet, and still have a safe load with good ES/SD numbers. How long has it been since you've cleaned your barrel with a copper solvent? That *could* cause this phenomenon. Otherwise, I'm at a loss... Happy Thanksgiving!

There are many published academic studies you can look up online for powder variation, lot-to-lot. Hogden 4831 was tested by the Air Force academy, and it showed high variations between lots. 96% of speed variation was accounted for by different lots of the same powder even when different brass, primers, bullets, or barrel length were used. Another study showed Varget to be a more stable powder. Maybe the powder you used was bad. I'd look it up.

Anybody got any powder recommendations for the 68gr Hornady BTHP Match bullets, I'm getting good accuracy with Varget but low velocities and I'm seeing flattened primers CCI #41's at .5 grains under max. At 24.5 grains I'm getting 2,628 FPS and it's jumping to 2,720 at 24.8 grains and the group is slightly opening up. The groups are great at 24.5 gr. and the velocity is decent at 24.8 but both are showing flattened primers and 24.8 is showing a drop in accuracy. I started at 23 gr. and the accuracy was good but the velocity was low as expected. This is out of a SS 18" Wylde barrel.

The RL15 suprises me. I load 24 grains under a 90 grain JLK loaded 5k off lands. Yes a 90 grain bullet.

I know this is an old video but I just noticed the primer stake marks. I haven't heard him mention what he uses. Any idea what kind of die he is using to do this?

This is wild as I use 24.0gr H-4895 in my BCM 16” and have a little swipe issue but not bad. WOA must have a much tighter tolerance but I’m also getting 2750fps 😅 out of my 16”

i am using RL 15 for my .308 45gr RL 15 hornady brass 178 ELDM OAL 2.83 still fits the mag speed i am getting is only 2600fps but good groups really happy with is powder

That's weird. I had pressure low with 77smk in LC brass but I found out it's due to my CLE chamber. I had to start lower than what the load manuals have stated.

How clean is your chamber from carbon ring? If you have carbon ring that pressure is giving you premature pressures....

After pulling these bullets do you resize brass to make sure you have consistent neck tension next time you load them?

My go to load for highpower is 24.1 RL 15 in Lake City brass with Rem 7 1/2 primers. Shoots great out WOA 20” barrel. I use the same load with Hornady 75 or Sierra 77 tips.

I load varget and RL15 both for 308 same powder charge, as far as 308 they seem to be very close to the same powder

did you make a spreadsheet with this data? I have a WOA 18" barrel and would love to know which loads shot the best. Can anyone tell me? I watched like 5 of these videos but didnt take notes - HELP PLZ

I have about 80-100 lbs. of nuclear medical lead containers. Are these good for bullet casting? Don't know if they are hard or soft.

Why not just reduce your load with H4895?

I noticed that the Sierra load data was using Winchester brass. Is perhaps the Lake City thicker, less case capacity? Just thinking.

Did you ever summarize at the end of all testing to identify the closest load found to duplicate the FC262 loading? If so, please post the link to the video.

The first thing I thought was short OAL and maybe bullet setback. Did you ever figure it out?

Odd, i use rl15 in a 24.0 grn load, (as per mk262 mod 0 military spec) and dont have any overpressure issues. I use an odin 18 inch dmr barrel as well

I found my mk262 Winchester 748 😁 yay

In my experience, stick powders work better with cooler primers. fed 205m is imo the best. WSR is best for ball powders. From a pressure spike perspective. YMMV

Johnny...so what is the best loading so far?? Do a follow up vid??? Found it! Vid 11!!!

Do you have a favorite powder for this load so far?

You haven't made a video on case annealing yet. Could you do that in the future?

If the reloading data was for .223 Rem, and you're using 5.56 brass, there is a difference in case volume. Maybe you just stumbled onto two powders where volume makes a big difference.

Can someone tell me if they still make 4895 haven’t been able to find it in years

Probably the primer.

any word on w748 video?

I loaded 24.7 rl -15 cci standard primer, seated 2.260 FC crimp removed brass,,, zero pressure signs 2781 fps 24 inch ar barrel 1-9 twist