6mmARC Switchback

kmw1954

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Jun 24, 2018
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SE Wisconsin
Purchased this rifle used from GunBroker and honestly the history is a bit shady. Was told it was a low round count but I have my doubts. After firing it the first time with some generic 80gr SP hand loads to set the scope I then later cleaned it. This took 20+ wet patches to get to where they would come out relatively clean. Didn't have a 243 brush yet as no one local had one on the shelf. Still got the scope set and it shot OK with these junk loads.

Next outing shot 12 rounds of factory Hornady Black. Had a major ooopps this time as I forgot which scope was on it. Thinking it was my 1/8 MOA scope I adjusted it as such and the first two shot again went into never-never land. So did a quick bore sight check and found it was now aimed way over the top of the target. There's the ooopps. The scope I have on this right now is a 1/10 MRAD and not the 1/8 MOA. Made a quick adjustment and was right back on target. BTW this was at 200yds. Again the rifle shot well but not what I expected. So when I got back home I scrubbed it again. This time with a brush and some Carbon Cleaner.

Yesterday while working the 200/300yd range I finally got a chance to shoot again after the crowd left. So I set up once again at 200yds. I also had 7 rounds of those junk loads left over so I decided to shoot those off first and make scope adjustments. Here now I had a clean, cold bore on a rifle I had not shot much. Those 7 rounds looked like a shotgun pattern. I then had a load I am starting development with. It's a 87gr VMAX loaded over BL-C2. With these I had short ladder loaded starting at the beginning load and working up by .3gr until I had 5 charge weight loads. First 5 looked like the junk loads as did the first 3 of the next. Then it started to group.

Really did not believe it would take that long to foul up the barrel and warm it enough to get stable but it is something I will pay attention to next time. In all I was not impressed with this load. I was told to disregard the BL-C2 but I have about 3/4lb left that I have no real use for. Though maybe it will work better with a heavier bullet. I also still have this bullet loaded up with Benchmark, A2460 and TAC. Hoping to shoot those on Tuesday.
 
So I have been reading. Yet to buy some though it is on my must buy list. Just bought 8lbs of Benchmark which is what I've been using in 223 and have loads for with the ARC.
 
Maybe hit it with a heavy duty copper remover. Savage barrels tend to be very accurate, but the internal finsh usually isnt as good as the outside. Ive found them to take more chemicals, or elbow grease, to get clean than one would expect
 
Thanks, but I think I've gotten it pretty clean. Again the history on this one is questionable. I think it had been shot much more than I was lead to believe. I'll see what happens next session. I've only got 25 rounds down it since I scrubbed it. Both my Savage 223 only took about 4-6 shots after cleaning to recover.

Also these loads could be long to a jam length as they were a but snug in rotating the bolt closed. I saved one and will chamber it and remeasure with the comparator.
 
Just finished chambering that last saved loaded round that I shot Sat. These were loaded to CBTO measurement of 1.731" which I thought was touch but again upon firing these they were stiff to close the bolt. This last sample after chamber and eject it measured 1.717".. Or .014" shorter. So these were definitely a jamb length.

When I shot the Hornady VMAX in the 223 they seemed to like a soft jamb as opposed to a jump. Now the other loads I have made up are also set to this length so question is do I push them back some or shot them as-is?

Picked up a 6ARC Hornady modified case to try with this rifle but can't seen to get repeatable numbers.
 
Just finished chambering that last saved loaded round that I shot Sat. These were loaded to CBTO measurement of 1.731" which I thought was touch but again upon firing these they were stiff to close the bolt. This last sample after chamber and eject it measured 1.717".. Or .014" shorter. So these were definitely a jamb length.

When I shot the Hornady VMAX in the 223 they seemed to like a soft jamb as opposed to a jump. Now the other loads I have made up are also set to this length so question is do I push them back some or shot them as-is?

Picked up a 6ARC Hornady modified case to try with this rifle but can't seen to get repeatable numbers.
Id try them set at recommended book length, then go out to touch if they dont do what you want.

I usually find that I don't need to jam bullets into the lands or even get them close really. Heck my 270 weatherby had .4 of jump, and my 257 is .25 at magazine length. Didn't have any issues with accuracy on those guns
The only gun im jamming right now it's my 28 Nosler, and that's to intentionally bump initial pressure to clean up the burn on us 869.
 
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That is interesting for sure. Had three lbs of LVR left over when we all had 30 30's. Back when it was 17$. Bought a 6mm arc barrel for my pro hunter. Messed with it some and wasn't impressed so I moved on. Maybe this summer. I've got box's of discontinued 80 gr Speer sp I'd like to use.
 
This is a brand new cartridge to me so yes I will be taking time to learn as much as I can about it. I know this was designed around a 105gr bullet and I have some of them to try. I shot some of the factory Hornady 105 in it and wasn't thrilled with the results. But again that was before I scrubbed the barrel out with a brush and solvent. So I will probably pick up one more box of factory and try again to get a good baseline.

Hornady has these seated much shorter and just from habit I start long and work back after I find a charge weight.

Also had to make a couple adjustments to the Boyd's stock after stealing it from my Savage Model 11. The bolt was tight and dragging on the magazine so shimmed out the bottom metal and the bolt release lever was tight and dragging on the inside of the stock making it hard to remove the bolt..
 
That is interesting for sure. Had three lbs of LVR left over when we all had 30 30's. Back when it was 17$. Bought a 6mm arc barrel for my pro hunter. Messed with it some and wasn't impressed so I moved on. Maybe this summer. I've got box's of discontinued 80 gr Speer sp I'd like to use.
From everyone I have talked to that is now working with the 6mmARC in a bolt rifle the consensus is the LeveRevolution even above Varget. I want to investigate lighter bullets to see if I can get the speed up. So right now that is 87gr to 95gr though I do have Hornady Match and Barnes 105gr waiting to load.
 
4 thousanths off lands a general rule for me.
And I have watched and talked to enough to know there is no general rule. Only the one the gun tells you it likes. I also have 2 Savage 223 bolt rifles and neither one likes the same thing.
 
Tomorrow I get to work the 200-300yd range. Weather is supposed to be rain, 40* and 12-15mph winds. I am expecting it to be dead as this will also be the start of our summer hours and now open Tue-Sun were we had only been open Fri-Sun for the winter months. So I will be taking this with me and if time and weather permit I hope to shoot.
 
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