Took the old girl to the range today. Loaded up some 220SMK that at my house(100 yd range) shoots lights out big holes. Today though as I'm making an attempt to walk her out to a grand, she starts throwing tantrums after 500yds. I loaded up 76gn of H1000 under some 220 SMK. CCI LRM and winchester brass. She hovers around 2876 give or a take a few. I use both Strelok and a Kestrel for a calculator, I do so for redundancy but mostly because I'm super familiar with Strelok but I'm trying to learn the Kestrel. Anyhow, this morning she was spot on dead nuts out to five hundred, from my table the 600 wasn't that visible so I jumped to 700 and I rang her at first but she started creeping to the right a bit. At 900 I was maybe 4 for 10 from the bench and at a grand I was just as reliable. All shots were taking from a bench, targets were either 8" plates or an IPSC. I was super disappointed because close in this is such an amazing load. Granted I don't have a hundred rds through this rifle yet but geez, what a kick in the ego.if I dialed it back to 500 it was spot on again but last that she was iffy. I tried the data on both devices, realized I made a BC mistake but corrected and never recovered. I just think she should have done better. Any opinions?
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MK13 Mod 0 load development range day drama
- Thread starter SFC RHYNO
- Start date
How many rounds on the barrel?
Also, pics of the Mod 0 are always welcome (up to you, of course).
I run the exact same charge of H1000 in my Mod 5 (I use Fed Mil date stamped 1x brass and 215M primers) and it drills holes as well.
Sorry about that. Sea Level in NE Florida= Hot as balls! It was 89deg and 86% humidity to be exact. My impacts and misses were completely erratic. I noticed part way through the morning that my NC in the calculator was wrong so I fixed that but it didn't make a difference. Also at 500 yds I trued the velocity, and I was shooting next to my LABRADAR. Really disappointed, I'm even willing to blame my form because I don't know how else to explain what was happening.
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Nice looking Mod 0, man.
I noticed a veloctiy change between 100 and 125 or so rounds, barrel sped up in my mod 5. It may or may not be happening here but for me it just showed up as being high on or air mailing the target when I was at the waterline when I had less than 100 down the bore.
Those conditions sound horrid, miraging was likely nightmarish. (I typically see 5-10% humidity). Could be a factor; fatigue, heat getting to you, target swimming through/in the mirage, etc. Maybe take it out again in a couple weeks when it cools off and see how you do.
Your absolutely correct, by lunch time the targets were swimming. Thanks for the kind words on the rifle. We had one like it in my company when I was on my second tour in Iraq. We would take it out from time to time, ofcourse back then I wasn't really a gun guy and had no idea what I had. Infact back then I just thought our M24's were weird for being 300WM. A couple years ago I got the bug to build one out so I took my time and found mostly original parts, other I had brought home with me. I had RWS put it together for me and I'm super happy with it.
8” plates at 1k are tough. The best F class guys in the world can only hold 10” with 22#, purpose built rifles and machine rests. IPSC should be doable, in those conditions but mirage combined with even a couple mph wind can move you 10” at 1k easily.
I’d try again very early in the morning if possible. Shortly after Sun up, or just before sun down. Conditions are usually flat then.
Also, you didn’t mention parallax, was it set for each distance?
I’d try again very early in the morning if possible. Shortly after Sun up, or just before sun down. Conditions are usually flat then.
Also, you didn’t mention parallax, was it set for each distance?
May be worth double checking your inputs for:
Bore height, barrel twist rate etc
Just for my clarification you are referring to your ballistic ap being off at 700 not group size correct?
Bore height, barrel twist rate etc
Just for my clarification you are referring to your ballistic ap being off at 700 not group size correct?
Here’s what works for me:
When I’m “truing up” a load for my Kestrel, I tend to ignore chronograph data.
I’ll input as much info as I have (bullet profile, twist rate, approximate speed, etc) and attempt to shoot a group on 20x10 steel IPSA target at 700yds with the help of a spotter.
When I’m sure I’ve got my dope, I’ll go into that gun profile menu for that load and adjust the muzzle velocity elevation up/down until it matches my real dope and then save it.
Then I move on to a 25x15 IPSA target at 1K, using the predicted dope in my Kestrel for 1K. It’s always good enough to get on target and I usually make a small adjustment if necessary.
I can’t shoot a further than 1K where I live so I usually call it good then.
The dope at shorter ranges is usually pretty close afterwards, but it’s okay to also adjust the gun profile for that range because the Kestrel will save that data (temp, velocity, etc) for that particular range too.
The Kestrel is not perfect, but it’ll get you close. Remember: garbage in/garbage out.
Search “weaponized math” on this forum.
That works, too.
And an 8” disc is pretty ambitious for 1K…..I shoot 1K nearly every weekend and the smallest target I can consistently (80-90% of the time) hit is a 20x10 IPSA aside from the occasional 1K milk jug challenge.
When I’m “truing up” a load for my Kestrel, I tend to ignore chronograph data.
I’ll input as much info as I have (bullet profile, twist rate, approximate speed, etc) and attempt to shoot a group on 20x10 steel IPSA target at 700yds with the help of a spotter.
When I’m sure I’ve got my dope, I’ll go into that gun profile menu for that load and adjust the muzzle velocity elevation up/down until it matches my real dope and then save it.
Then I move on to a 25x15 IPSA target at 1K, using the predicted dope in my Kestrel for 1K. It’s always good enough to get on target and I usually make a small adjustment if necessary.
I can’t shoot a further than 1K where I live so I usually call it good then.
The dope at shorter ranges is usually pretty close afterwards, but it’s okay to also adjust the gun profile for that range because the Kestrel will save that data (temp, velocity, etc) for that particular range too.
The Kestrel is not perfect, but it’ll get you close. Remember: garbage in/garbage out.
Search “weaponized math” on this forum.
That works, too.
And an 8” disc is pretty ambitious for 1K…..I shoot 1K nearly every weekend and the smallest target I can consistently (80-90% of the time) hit is a 20x10 IPSA aside from the occasional 1K milk jug challenge.
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I’m still stuck in 2001, and don’t use a computer yet. I run my data through JBM, write it in a notebook and go test at 200/300/500/600/750/1000 and 1250 if I’m shooting worth a shit. Real come ups get recorded, as well as temperature and hit percentage of (usually) 10 shots. Wind obviously has a say in my success as well.
I try to do this at 30*, 50*, 75* and 90*. This makes up the card I tape to my stock.
JBM is close, but not all scopes are created equally. I mostly shoot Nightforce and as long as the come ups are repeatable I don’t sweat the inconsistency with the computer data. Real world dope trumps everything else IMO.
My 700/300 didn’t shoot H1000 and 220s worth a shit initially. I switched to Retumbo and 230 OTM Berger at 2780 FPS in Winchester blue bag. Tightened right up and shoots around MOA at 1k. 1250 it’s opens up. Could be me, could be the load, though it shows stable to 1500 yards. The rifle does shoot mk248 mod1 well. At 1k it’s 10” flatter than the 230OTMs and holds amazing elevation but it destroyed every piece of brass. Massive ejector flow.
I try to do this at 30*, 50*, 75* and 90*. This makes up the card I tape to my stock.
JBM is close, but not all scopes are created equally. I mostly shoot Nightforce and as long as the come ups are repeatable I don’t sweat the inconsistency with the computer data. Real world dope trumps everything else IMO.
My 700/300 didn’t shoot H1000 and 220s worth a shit initially. I switched to Retumbo and 230 OTM Berger at 2780 FPS in Winchester blue bag. Tightened right up and shoots around MOA at 1k. 1250 it’s opens up. Could be me, could be the load, though it shows stable to 1500 yards. The rifle does shoot mk248 mod1 well. At 1k it’s 10” flatter than the 230OTMs and holds amazing elevation but it destroyed every piece of brass. Massive ejector flow.
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Well, might I inquire about your bipods? In the picture shared they look loose and I cannot tell but they appear to be the not cant version?
Additionally have you tried any of the 190gr SMKs loads? I know a lot of guys chase after the Mk248 Mod 1 clone loads but I’ve honestly found the the Mod 0 to have the edge in accuracy and the reality is at the speeds you can sling them in a Mk13 they will probably be close to 3200ish (if you go super spicy) which is fairly respectable.
I shot Mk248 Mod 0 in Afghanistan exclusively because of this in spite of having Mod 1 as well.
Lastly also maybe consider an OG A191 loading and run some Lapua D46s, the rebated boat tail design is something you don’t see very often these days, but those bullets rock and would be cannon for an early Mk13.
Additionally have you tried any of the 190gr SMKs loads? I know a lot of guys chase after the Mk248 Mod 1 clone loads but I’ve honestly found the the Mod 0 to have the edge in accuracy and the reality is at the speeds you can sling them in a Mk13 they will probably be close to 3200ish (if you go super spicy) which is fairly respectable.
I shot Mk248 Mod 0 in Afghanistan exclusively because of this in spite of having Mod 1 as well.
Lastly also maybe consider an OG A191 loading and run some Lapua D46s, the rebated boat tail design is something you don’t see very often these days, but those bullets rock and would be cannon for an early Mk13.
