• This topic has 8 replies, 1 voice, and was last updated 4 years ago by Anonymous.
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    • #29894
      Anonymous
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      I have two similar molds, one is an RCBS 309-200- Sil and the other is a NOE 316-200-Sil. Both have one cavity gas checked and the other cavity is Plain Based. I use the RCBS in my 30/06, 30-40 Krag and now 308 Win. The NOE I use for 303 Brit and am going to try is for 7.7 Jap. My question is should I throttle back my loads for the plain base. My alloy is 15 BNH as ingots and I am water dropping. I do not try to push to the max load listed but have approached them in finding my most accurate loads.

    • #29896
      popper
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      Depends on alloy, fit, lube, powder, accuracy criteria, etc. IMHO, start at ~1600 fps and work up. 2200 will be difficult. Might try with LeverE or other small kernel powder, stick seems to peen the base a lot. Plan on keeping the base inside the neck. I did get 1750, PB 150gr. in 308MX accurately (chrony @ 50) using 4227.

    • #29898
      Goodsteel
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      The GC is a mixed blessing. It doesn’t work very well if it’s not needed.
      Part of this is the pressure required to make it take the rifling and form to it correctly. If you’re running reduced loads in the 1400-1600FPS range, you’re likely to have accuracy issues (unless all you’re looking for is a bunch of bang and a spray of random holes on the paper).

      One thing you can do to greatly help in this speed range is to try a side by side test of annealed checks vs. as received checks. Often, placing them cup down on the bottom of an old skillet and hitting them with a torch till they are red hot momentarily will show an impressive accuracy gain. Sometimes not. Do a test to see if it makes a difference with your rifle.
      You might also play with uniforming the checks so they are truly flat on the base and fit your bullets perfectly (although this may be too subtle a gain to observe).

      Use ten shot groups, and tune your load one thing at a time. You’ll quickly find what works and what doesn’t.

      If it were mine, I would use excellent cast bullets with no wrinkles or defects, and I would do what it took to make sure that after lubing and checking, they were all the same length (you know if they are long, it can only be one place, and the likelihood of that check being square to the base of the bullet is almost nill).
      I would cast a bunch of them and maintain as much consistency as possible till I had at least 250 good ones (both PB and GC).
      After that I would work on getting them into the necks of the brass without damage using the NOE expanders.
      Then I would work the powders with ten shot groups till I found the best charge for three likely candidates, then compare each of them in side by side tests.
      Once the powder is selected, work on neck tension.
      Try different primers.
      Rework your charge once more and put a fork in it.

      Step back to the next most likely powder and repeat. If changing neck tension or primer suddenly makes it play better than the best powder, then voila!
      This sounds like a ton of fiddling and shooting, but honestly, you’re only looking at about 100-150 shots to find the sweetness for either style of bullet. You can do that in one range session if you adhere to scientific method and have the ability to make changes on the bench.

      Once you know what the GC bullets act like, take the next 150 shots and stroke in the PB. The results might surprise you!

    • #29899
      Anonymous
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      Tim, read your post on uniforming gas checks with a drill press and a chunk granite, I think it was, sometime back. I finally got myself a piece of granite that is flat and smooth (polished in fact).
      Have a drill press, now I need to read your procedure again! Can’t remember how long back that was. On this forum or CB? Thanks for the advice Tim I will be working on it for sure.

    • #29901
      Goodsteel
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      It was NOE forum IIRC.

      Regardless, it basically involves measuring the base of the bullet, and buying a gauge pin that measures exactly that size, then putting the pin in the drill chuck.
      use sand paper under the tip of the pin to flatten it perfectly by applying very light pressure while pulling the sheet of sand paper from under the gauge pin while it is spinning.
      Once that’s done, just put your checks on the tip of the punch and press them against a flat surface while spinning at about 400-500 RPM.

      Using this method, you will probably get slightly concave checks that are PERFECTLY SPUN AND UNIFORM.

      When installed on the base of the bullet before adding lube, my tests indicate a measurable accuracy gain.
      Mark my words, the base of the bullet is the most important component of accuracy, and for us, that surface is a stamped piece of copper that looks like a potato chip unless we fix it.

      Again, don’t get carried away with this. It’s a PITA, and maybe not necessary. Only a side by side test in your rifle can determine if the results are worth the work.

    • #29999
      Larry Gibson
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      retread

      The GC’d bullets will more than likely give best accuracy (depending on powder) in the 1600 – 1950 fps range. With either bullet I would simply try 28 gr 4895 and a Dacron filler. An alloy of 94/3/3 up thru #2 with the bullets WQ’d out of the mould would be my choice. Hornady GCs and Lar’s 50/50 or 2500+ lube is what I would use. Actually all the above is what I did use with a 314299 that dropped at .3155 with #2 alloy when I loaded for a reasonably nice 7.7 jap a few years back. Still have the mould and the dies.

      The PB’d bullets will give the best accuracy for 100 – 200+ yard shooting at 1200 – 1400 fps. For powders any of the usual suspects between 2400 up through 4198 would be good choices. If cast soft and TL’d in LLA they will also do very well at 800 – 1200 fpsver Bullseye. You may want to drill the flash holes to avoid the cases developing short headspace with such loads.

      Larry Gibson

    • #30004
      Sgt. Mike
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      Larry Gibson;n9593 wrote: retread
      …….The PB’d bullets will give the best accuracy for 100 – 200+ yard shooting at 1200 – 1400 fps. For powders any of the usual suspects between 2400 up through 4198 would be good choices. If cast soft and TL’d in LLA they will also do very well at 800 – 1200 fpsver Bullseye. You may want to drill the flash holes to avoid the cases developing short headspace with such loads.

      Larry Gibson

      Still have that to play with those loads Larry, the cat sneeze loads would be interesting for getting back to basics.

    • #30026
      kungfustyle
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      Always learning something. Thanks for the posts people.

    • #30031
      Anonymous
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      Thanks for the post Larry. Your advice for the 308 worked well right out of the chute. I will be tinkering, looking for the real sweet spot for that rifle but for the first go round it was superb. Now to try the 7.7.

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