Cloning MK 248 Mod 1 - Part 1 - 300 Win Mag
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- Опубликовано: 4 сен 2020
- It's time for a new 300 Winchester Magnum reloading series. We are attempting to clone the performance of MK 248 Mod 1, a military round that uses the 220gr Sierra Match King.
/ johnnysreloadingbench
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Don't even have a 300WM... I'm just here for Johnny's expertise
Same here. only have 2-3 calibers hes shown but that doesnt make any if the videos any less interesting
Amen, I always learn something. Even if I don't handload the cartridge.
Took the words right outta my mouth!
Oh I think I can find a use. I have been looking for some of his knowledge on a caliber I happen to enjoy. Now if I can get some 338 Lapua love life would be great.
Don't stay long you will end up with one yourself!!!!!
Johnny sold those 3 pulled primers and was able to buy a new car.
Damn bro I thought this comment would have been more recent. Really hurts a bit more to see it's 5 months old
@@sallyann8971 even worse when you see local ads for H1000 for $180-$200/lb. People are nuts!
@@Breezio69 bro I actually had some luck at home last week at 3 different local shops for powder primers bullets and brass for a almost normal price. So much luck I spent all my scope money. And one shop had a pallet of small pistol primers and I walked away as I don't load.
Maybe this will all be over soon.
@@sallyann8971 hope you're right. Best odds of me shooting 300win is reloading which is why I'm looking at these vids.
U.S Military covertly gets ammo to Johnny and secretly watches him play around with the load to see if he might improve it ......my first conspiracy 🤔
@wildcat reloading. Haha, I was thinking the same thing.
Lol
Leave it to Good Ol Johnny
That would make too much sense...definitely a conspiracy
@NLH350Powered think about it. Compared to the funding and resources the military has, they come up with a rather "mediocre" but if someone with basic equipment who pays out of their own pocket improves it and publishes it in a videos format, its free labor and its saves the guys in the lab a failed light bulb or 2 because all they need to do is emulate and see if it works, rather than spend time and devise plans that wich cost money and effort
So I did this a few years ago... Sorry for the long message but I think it'll be helpful.
I bought a load MK248 fired brass at auction from Anniston (like 600 lbs IIRC) and there were a few dozen primed/unfired cases in the lot. Headstamps were Federal 13 and 14. I prepped and trimmed some fired brass and trimmed the unfired/primed brass to the same length, then loaded identical charges of H1000 with the 220 SMKs in the new brass, the FC13, and the FC14 brass with both 210Ms and 215Ms in the FC13 and FC14 brass.(10 FC13 210Ms, 10 FC13 215Ms, 10 FC14 210Ms, 10 FC14 215Ms, and 10 in the primed/unfired brass for a total of 50). The performance in the FC13 and FC14 brass was identical with both primers, so I was really shooting 20 identical rounds with the different primers to compare to the 10 Federal MK248 primers. In addition to having a significantly lower SD and ES than the 215Ms, the 210Ms duplicated the performance of the factory MK248 primers exactly (duplicated to within 8 FPS average). While I would stop short of saying that I'm 100% sure they use 210M primers, I can say with absolute certainty that the 210Ms perform identically to the factory loaded primers.
I ordered some MK248 from 2 different sources to get 2 different lots, and worked up a clone load in a 24 inch Douglas 10 twist and a 28 inch Broughton 10 twist with the Federal brass, 210Ms, 220SMKs, and H1000 and matched the velocity average of the factory stuff in both rifles with the same load. Except my loads grouped sub 1/2 MOA while the factory ammo was just a hair over 1 moa. I attribute the difference to me weighing every charge.
I've used Federal 210Ms with H1000 for other cartridges in the past and they're just a great combo. Very low SD and ES with tremendous accuracy potential. (Remington 7.5s and 8208 XBR is another match made in heaven, but not for the 300 WM; I would suggest trying them together in your MK262 clone series. It's like magic).
Anyway, DETAIL SPECIFICATION
CARTRIDGE, .300 WINCHESTER MAGNUM MATCH, MK 248 MOD 1, DODIC AB43, NSN 1305-01-568-7504 does specify a 24 inch test barrel.
And try a Forster Co-AX. Beats the pants off the Hornady :)
I’m gonna give your info a try. What rifle u running?. I’ll be running rpr. May do a vid also. See how video goes. I’ll be in touch.
I’d be really interested to see the sequel to this. Especially the difference the brass prep makes, annealing vs not and how it affects velocity.
The things you do apply to any rifle cartridge. I enjoy your process, and the way you vocalize your thought process. Keep up the excellent tutelage.
The MK262 series is my favorite series ever in the history of RUclips. Can’t wait to watch this! Thanks Johnny!
Great videos. Just to throw this out there....I reload 300 WM also. I had a lot of issues with case separation also. I called the die company...no real help. I ended up going to my gunsmith...he is normally a bench rest guy. After telling him about my case issue, and showing him my brass, he laughed at me and educated me. He said with a belted magnum, it is impossible to use the normal head space gauges and get it right. As you know, the case head separation is do to the case being over sized, and it stretching a ton each time you fire it. He showed me how to fix the issue. Take your bolt apart so there is no spring tension , so the bolt handle should just fall closed on its own when you close the bolt. Load a fired case and the bolt should not just fall, but have some friction. Start sizing your case bit by bit and checking in your chamber. Size until the bolt will just fall all the way down on its own. Size all your brass to this. Since I have been doing this, I have not had any case separation. Its a bit of extra work, but seems to be the answer. Feel free to contact me if you care to.
This is one of the most helpful comments I've ever read on any YT video. I'll be trying this later tonight on my M70. I've also got one in .338winmag and while it hasn't been as prevalent, I have seen case separation at times as well. I take it the above process can be used with any belted magnum? Thanks again for posting this!
There’s always more than one way to Va skin this cat! Belted cases only head space on the front edge of their belts, DUH! I had my 300 Winnie Mag’s chamber, “neck throated” +.050”. I reformed cheap pull downs, 300 Wea. Mag never fired brass and trimmed the necks to 0.314”. The long way around the block, but the Winnie Mag @ 165 grs. Bullet is the largest 300 which Hogdgon’s list reduced H 4895 loadings for. I’ve reduced some to 308 Win. Levels. If I FL Resize them in my Remmie M 700’s chamber, after firing, I still have 0.304” long necks. Circlip extractors keep cases centered in Rem’s sloppy chambers, but for Big Game hunting, Factory ammo is still the way to go? BTW, GS only charged $20. to neck throat My new SS take off barrel. Shoulder doughnuts haven’t bitten me yet😇!
The same applies to any case. In case you don’t have a head space gauge like Johnny just adjust the die according to the procedure above and have minimal stretch of any case.
The range sessions for this video were streamed live on twitch. In the future, I'm going to be streaming all of my range time as well as a Q&A/Chat stream every Tuesday evening at 7PM Eastern. Follow me at www.twitch.tv/johnnysreloadingbench and join us next time!
Wanted to tell you I just got back from testing. 300 blk hornady 125gr with 19.0 of h110. That is spittin 2031 out of a 7.5" Q sugar weasel!!. I love it! Also my favorite subs are 208eld with 12 of CFe blk!! Thanks for all the content! I have only been reloading for only a month and have learned a ton! Thanks again!!!!
I just got to the part where you measure the powder weight and it made my jaw drop, I've loaded 77grains of h1000 in a 300wm with 220grain smks before, very compressed and lots of volcanoing of the primer.
Also what scale is that? I have been having some issues with mine lately
Cz-Bundy he has a digital scale comparisons video
@johnnysreloadingbench get more bushings. Leave dies in bushings. No more fussing with the bushing. Plug n play
That box of MK248 MOD1 must be worth at least $1k at this point... haha
JRB: "This die was $164 so we'll have to save a lot of brass to cover that cost..."
(Nosler 300 Win Mag brass enters the chat)
I would also add that Federal brass is notorious for the primer pockets getting loose... You'll likely end up canning them for the pockets long before case head separation would be an issue.
I'll never own or reload a 300 Win Mag, but I watched the entire video. Your presentation is always entertaining and I can always pick up something that I can apply to my own loads/testing.
Thanks much, Boss. :-)
I do own and shoot mine allot, I’ve rebarreled mine twice and it’s my go to rifle. I’ve been looking at a heavier bullet load for long range
Kodeeni how many rounds before rebarrel?
Jeremy S
It will depend on the type of barrel, my rifle ( David ) is a Stainless Remington 700 so the barrel lasted longer then a blued barrel. You will see accuracy drop off first as the throat wears. Then suddenly you wont be able to hit squat. Mine happened 6 weeks before a moose hunt in BC, I never really counted the rounds but was told by my gun smith that its somewhere around 800
Kodeeni wow. My dad has around 5k rounds of 308 win through his 1993 Remington 700 bdl varmint and it will still shoot 1/2 moa all day long
Jeremy S
The 300 Win Mag has allot of slow burning powder going down the barrel where the .308 has less and is slower. So the higher round count makes sense. My 300 shoots just as tight, 1/2 at 100 and when I had better eyes I shot a .234 3 shot group at 100. David is not a stock rifle, he’s had 3 barrels, 3 Stocks and 2 different triggers. Is glass bedded with a new Leupold scope
My lord I need that storage rack!
I certainly hope Steve reaches out!! If anyone has any info I am very interested.
Hey Johnny, in the publication you read about the military round, it said they put an additive for flash suppression. That could account for the heavier powder charge and compressed load required to push the factory round to the speeds you we’re getting with a lighter charge. I think if you go even a bit lighter you could find a good node. I enjoy watching your vids!!! Great job!!!
I don't really have a use for a 300 WM, but vids like this make me want one anyway
Oh I do. This is exciting. It's a fun cartridge. Nice thump. Big boom. Lots of power.
ha,ha,ha, Scott! everyone has a use for a 300wm !!!
You don't just need a WinMag.... You NEED a 300 WinMag!!!! They are just AWESOME!!!
I have an open cart at MidwayUSA.com while watching these videos for all the things that I have no use for (but I now need).
It's a great addition to anyone's collection.
Ps...after watching a crapload of other reloaders, I have to say, your setup and delivery is the best. I appreciate all the good info and the mistakes, realistic and helpful.
Glad to see you are back Johnny. Thank you for making such fantastic and informative videos.
Just go back out there and shoot that last group. Pressure signs were fine, compared to the other brass, and s.d. and e.s. was getting better. DO IT!!!!!
I enjoy watching your videos. You do a great job of editing, and you also do a great job of shooting. Thank you for your scientific approach of changing one variable at a time and thank you for the time and energy that you put into these
A great video for us reloading freaks and fans.
Mannnnn I just built a 6.5 creedmoor, now I want to get a 300WM. thanks JRB!!!!! Love the videos no matter the caliber. Keep up the great vids
It’s a lot more recoil! I hope you have a thick shoulder...😄
This video was worth the wait. I'm amazed at how accurate and reloader friendly these Thompson Centre Compass rifles are, especially at the price point.
Looking forward to the next one
Gawd I missed these.... best hour and a half I’ve spent online in months. Thanks Johnny!
Peterson Cartridge Co. just released their 300 Win Mag brass, definitely worth looking into. Took our 300 Win Mag load w hornady brass putting out an SD of 20 down to an SD of 2... just with a simple brass swap, same charge weight, same primer, same projectile. Plus they have a new 300WM Long case to consider as well, head spaces off the shoulder to prevent that initial 10-15 thou jump and saves brass life.
This is a hot load out of Mk13 and M2010's in service. Normally I fire the 190gr SMK, Mk248 Mod 0 out of a Mk13 and get .5-1" groups. Barrel for the Mk13 is a 26.5" 1:10. Remingtons M2010 are a tad shorter at 24" also 1:10 twist
JRB
Enjoying your videos. Nice to see you back. I started reloading and its because of your videos that's something you should be very proud of. I really wanted to say THANK YOU. Your truly appreciated. The best reloading videos I've ever seen. God bless.
This is going to be a great series. Can't wait for more episodes!
I love the way he keeps it real
Duuuuuuude! How much I miss you and your videos! Keep them coming, you are a "special kind" of person!
Always informative, always entertaining. Thank you.
So glad you are back. Hands down best reloading content on RUclips.
Thanks for all your hard work.
When you go from one type of powder to another the 1st and sometimes the 2nd shot is not going to be in the group. It has to do with the residue that each type of powder leaves. It is kind of like a cold clean bore 1st shot. Always send one round into the dirt before you actually try for a group. Hodgdon powders seem to be more affected by this than others
Good to see a standard JRB video! Welcome back Johnny!
Great stuff Johnny !
Got to say, loved your 262 clone series. Was able to work up a load with 2520 that shoots one ragged hole at 100 yards. Sameat 200 yards out of my mk 12. Hope this clone is as successful! Thanks for your hard work!
great video as always, i too got tired of the lock n load system, also my bushings and dies would lift every time a shell was raised into the die, enough that I was sure something was up, support was no help so I removed their bushing adapter from the press and went with a normal Lee screw in one. I squared off two sides of one of their LnL bushings with a hack saw so I could put a wrench on it and out came the adapter in the press no problem. What a difference using a normal Lee threaded die socket, bullet seating depths are now a lot more consistent and all the other frustrations are gone as well. Please keep the videos coming, always informative and unbiased.
Good to see you back on the bench buddy
I got tired of my lock and load bushings so I epoxied one in no more issues I really like your videos keep doing what you’re doing
Hay Johnny broke this down in few days of watching. Great video. I say got good load in the work for hunting for sure with those groups.
I love your cloning videos!
The Magnums are fun to shoot, i have a 7MM Remington Magnum (Weatherby) From looking at your groups, the first shot in all three groups are low and to the right. That either in your load development or your trigger control.
Hey Johnny, thanks for coming back Bud. Really appreciate what you do on here. Bought some stuff to start loading 6.5 creedmoor. Having trouble picking a gun though being a Lefty. Torn between the savage 110 tactical or christensen arms mesa. Although there are plenty of other options I wouldn't mind either.
Being a left-hand shooter myself I opted for the Tikka t3x tac A1 and I have never been happier with a firearm in my life
@@joe74ta1 saw that and really like it. However the 6.5 I get has to be a jack of all trades. 95% just shooting paper or steel but 5% hunting. Not sure just how much weight I'm willing to lug around. I'd say the tac A1 is on the table but is towards the edge of it.
Thoughts?
Yay. Thanks for the 300 Win Mag episodes again
Great to have you back in action! I hope those pockets hold up for a few more cycles. I would try a different press so you can run the collet die before you size the rest of the body. I would suggest running a test using an arbor press with a force pack now and then. Just to check the processing. It gives a better idea of the condition of the necks by measuring the seating force so you get some feedback on annealing and bushing selection, etc.
Great to see videos coming back man!! Try standard large rifle match primers. Noticed a huge difference on my 300 wm when switched from magnums. Pressure signs backed right off and groups improved. Also velocities backed off a bit in my rifle gave closer to advertised. H1000 runs fine with standard large rifle primers. Look forward to future videos man. 👍🏻👍🏻
Welp my days a bit improved, always love the videos, glad your able to make a few again. Hopefully ya dont have to drop down to 1grain increments and 2 round groups to save primers haha!
I love these thorough videos!
Hodgdon load center says 78g of H1000 for a max charge with a 220. 🤷🏻♂️
160 for a single die, what a baller! Please keep putting out videos regularly.
Just looked up the Sierra Data
24" barrel, 1-10" twist
For the 220gr HPBT Match stock #2240 3.340" OAL
They show a max charge of 74.5gn of H1000, for 2800fps/3829 Ft. Lbs
They also show a max charge of 79.2gr of Magnum for 2830fps/3912Ft Lbs
I don't even have anything in this caliber, I'm just happy to see you making vids again
Johnny its such a pleasure to watch your videos 😁👍👊🇺🇸
Nice. Been waiting for this one.
This guy!? A loading junky if ever was one! Love the information you share Johnny from experience, on video no less! Keep up the great work my friend and may your habit never die!Can't say that for most junkies with thier habits!🤣🤣
Great videos!
Keep'em coming!
I always adjust the full length sizer dies to just size the neck and not bump the shoulder back much if any. The die sizes the sides of the case a bit but doesn’t set the shoulder back, helping keep the fire form somewhat and not over working the brass. I have a .338 win rifle and that brass has had about 4 loads on it now and shows no signs of giving up and the primers still seat with good tension. I run a 250 grain bullet at about 2760fps so it isn’t a wimpy load.
Those are sweet. Steve hook us up with the file!!!
His link is pinned
Good work johnny. I just dont feel like i have enough time to go down and load bullets and shoot working at the hospital and having young kids and your videos give me that serotonin rush i need to get through another hellish day. Keep up the good work.
Thank you Sir! I don’t have a 300 win Mag but I sure miss your videos!
I need to see video 2! I love this!
Such a ubiquitous cartridge in hunting and military use. I've loaded many for friends' hunting trips. 220gr Nosler Partitions. Such a versatile cartridge.
Always great content, thanks Johnny. 300WM is so versatile. You should do some load testing down to 110gr.
Sweet finally something to keep me occupied at work
May I request (if it’s not too much pressure) a closing video to the mk262 mod1 series? Just go through what we learned, the best loads, and maybe untested loadings or powders that still have potential. May just summarize the success you had. That would be awesome. I’ve been trying to go back through and rewatch all those videos, but there’s SO MUCH CONTENT it’s almost impossible to track it without a spreadsheet. Thanks man!
Great video
That comparator stadium is bad ass!! I literally google searched exactly the name you gave and voila bought one from him for 30 bucks
Great job
That storage stadium is great!
New JRB. And some 300 win mag love. My day is getting better.
Finally. Thank you.
Glad you're going to stick w H1000 for some fine tuning. Really good start!
I’ve had similar feelings with the lock n load bushings. I’ve contemplated using JB weld on a bushing and call that my conversion.
I did that to my press and has worked great!
Best thing I've seen for the lab radar is a piece of brass to aim it with works great
Great video Johnny, I have spent the last year researching different products for the build have a 300 Win Mag. I intend to building a gun around a 208 grain ELD m, and be consistent MOA at a 1000 yards . But with no more recoil then a 308. This whole video will be of great interest to me on the powder and muzzle velocity attained. Keep up the good work.
I shoot that bullet at 2860-90 fps from my Criterion and 4" hangers at 600 with a 10x42 scope is readily attainable. SUB 1/2 MOA is easy. That was a Criterion Match chamber 28" bull. Now recoil... Well get a good break!
@@ewetho for recoil I plan on going with a chassis and a Mercury buffer and a Terminator 4 brake. If you don't mind what powder are you using to get the 2860 - 2890 fps?
@@cecilandrews1875 H1000
Don't know if this was mentioned elsewhere in the comments. "FC-" is the lot manufacturer identifier for Federal Cartridge as in Federal Arms that make the primers used in this video. New standard lot numbers for the DoD is 3 digit/letter manufacturer (if three digits are not used then a 2 digit and a dash will be used), 2 digit year, 1 digit letter for month skipping i, then 3 digit - 3 digit build sequence. So FC-11M350-034 Federal Cartridge, built in 2011, December, build sequence 350-034. If anything changes between brass, primer, bullet, powder then a new build sequence is created.
The 220MK load by military was very hot destroying primer pockets with H1000.
Hard on throats also ! In the military the 190gr MK load with RL 22 was a winner in the 300 Win Mag. The 190MK load used RL 22. Yes the 220 MK load was discontinued! More kills in Iraq went to the 190MK with RL22 at 71.9 @ 3.464”.
Really appreciated the video. The idea of reducing the neck tension seems like a great one to get those pressures down a bit, and perhaps get better results. Have you considered using a long drop tube for the powder say 10 inches or something longer? Might allow you to get some more powder in there and be closer to the noted grain number. Also seems like that flash suppressant could be a factor here.
“A big ole long throat.” Huh, knew a cheerleader like that once…😂😂😂😂😂😂😂😂😂😂😂
Johnny........................He's back !!
Great Video, I don't have a 300WM but I enjoyed this first video ..... keep it up !!
I would like some info on the bushing tray......it looks like a winner, I hope he has
a paten on it ??
I was able to pickup a bunch of CCI No.34 primers at a local gun shop here in Florida. They look exactly like the ones you punched out of the case.
I reload for my Parker Hale 300WM. I have been using a 1974 Speer manual and a 2012 Lee manual. The Speer states that I can use IMR4895 to push 200gr Spitzer bullets: 52 to 56 gr 2411fps to 2602 fps. I made a few and will try them soon. I regularly use H1000, Federal magnum primers and brass, and 180gr Nosler partitions. I only hunt moose. Great video.
Amazing content! Still trying to decide on a reloader for my 300 wm!!
couldnt stand to sit through the live stream but this video is the best and i dont even have any interest in 300 mag of any kind. Be sure to hit the like button to let youtube know that this is the type of content you want to see. I would like to see some 22-250 or 38/357 videos in the near future though.
Yes! Yes! Yes! Although the document says "Chamber pressure shall not exceed 78,900 PSI" not 68K that you mentioned. Guessing that was a slip of the tongue.
I love these long ass videos
Thought we might see the face get blown off! That is crazy velocity for that bullet and barrel length. Keep em coming
Long throat plus still a reasonable charge - he’s fined. I think when I last shot wm with the 240’s I was running around 73.5 grains of H1k. I’ve moved on to 37xc 338 lapua and 300 norma for elr anymore.
Yeah I’ve done load development for 300 Norma and gotten 250s up to around 2900 fps but there is way more case capacity in that case than 300 WM. I shoot the 200s in my WM and a little over 2900 fps but to me that still seems a little fast for 220s. Especially out of a 24” barrel.
Awesome video as always. Thanks for making these. As I've remarked on other videos I see myself watching reloading videos on calibers I have no interest in. If I'm in that window I'd be looking for a 7 mil rem mag yet again between your having ammo that is questionable and your willingness to share the info here I am. You Rock bud.
Thanks for the heads-up about the twitch streams!! I have really missed your videos!! That comparator rack is AMAZING!!!
STEVE IF YOU SEE THIS MESSAGE PLEASE PLEASE PLEASE REACH OUT!!! THAT COMPARATOR STADIUM IS GENIUS!!! I AM VERY INTERESTED AND MANY MANY MANY OTHERS ARE AS WELL!!!
Even though its a hot AF round im going to give it a shot
I load 175 grain bullets in 7mm Rem Mag. 200 yard groups will often be almost the same as 100 yard groups. I will be looking forward to seeing some longer range results.
Freaking awesome!!!
Steve, whoever you are, please, take my money! I NEED that stadium storage.
Now I need a 300 win mag
I used the M24 long action sniper rifle in the ARMY. It was chambered in 308 and after the first learning less in Afghanistan the our M24's were chambered in 300WM. So my next visit to buttcrackastan we were the teachers. I love the 300WM so much I own two now and my favorite go to 300WM has the Teludyne Technologies straight jacket system on it and it's not a barrel burner any more.
There Remington magnum match primers. They are colder primers overall. I use them in my cast 308 loads with the 210g lee
Think you’ve got a good load going here. Would love to see what effect seating depth has on it! Maybe stretching it out closer to where you were before and trying increments of 0.002-0.003” once you get a charge weight with low SDs dialed in.
I was really hoping for a second and 3rd video.
I've got 220 matchkings, but instead of directly copying the load itself, I'll tailor it to my gun. It doesn't have to duplicate exactly. I didn't even know they were running 220s for the military, but nice to know my thought was right for what I want to do.
Case volume differences translates to OAL variance when loading compressed loads.
In the middle of the video I went and tried out my Lee collet die and it was like butter. I have used and sent back a standard lee 300wm die and it sticks cases like crazy. I'm probably going to order the lee collet die for 7mag.