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tomv

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Everything posted by tomv

  1. Agreed, however I think the benefit if shooting identical guns, except for their weight, is that both divisions benefit whenever you practice or compete with one of them. my two are about 12 oz different and because the 22 weight savings come from removing the buffer and Mag adapter and a lighter bolt mechanism they both point and swing about the same. I also have a Volquartsen Ultralight barrel and receiver on a Mod Shot chassis. That weighs 3# 9oz, about 1/2 pound lighter than the AR22, and I'm faster with the AR. I think that is because I benefit from shooting the same geometry in two divisions.
  2. I built a dedicated 22 to keep things simple for me. Because it's a rimfire I was able to use a post ban receiver for $100.00 instead of a $1200.00 pre ban one (required for centerfire guns here in CT. That made the build seem very cheap to me. The most expensive part of the lower was the Hiperfire Eclipse trigger. Since I shoot Steel Challenge RFRO with it it was a no brainer for me.
  3. Is your lower a 5.56 with Glock mag adapter? If so then all you need to change is the upper, remove the mag adapter and buffer (not necessary for operation but saves weight) and you're good to go. Use Black Dog 22 mags which fit right into the 556 mag sleeve and are the most reliable. For the upper I used a CMMG 4.5" 22 LR barrel and their 22 bolt assembly. You can buy these as a set from CMMG. I sent mine to Tim at Taccom and he welded on a shroud to get the bqrrel to 16" and completed the rest of the upper. I just use a piece of pipe insulation for a handguard. If your lower is a native 9mm I'm not sure what to do. I know that Glock makes .22 pistols but have never examined the mags to see if they are the same geometry as the 9mm. You should call CMMG and ask whether Glock .22 mags will work with their bolt assembly.
  4. We run 62 PF loads in our 9mm Steel challenge guns. Mine are the two ARs pictured above submitted by jdoran. The 9mm weighs 5#, 14 oz more than the 22 at 4# 2oz. There is very little difference in dot movement between the two. Biggest difference is that CCI minimags run at 1250 FPS while the 95 gr 9mm loads are down at 650.
  5. Nice gun. How much does it weigh? Are you using Taccom bolt and buffer?
  6. What color is your recoil spring? How many Tungsten weights in the buffer? You can reduce the spring weight and or change Tungsten weights for steel. Tungsten weights look like a dull grey, steel looks shiny. If you look on JP website there is a guide to the colors vs weights. I shoot steel challenge so don't have to make power factor. The 9 mm spring supplied with SCS and spring are way more than I need. In tuning the gun I found that standard 5.56 springs are lighter than 9mm so I'm currently using the lightest spring (white) and all steel weights in my 4 weight system. Before going this route I tried short stroking my gun to get bolt speed up with 70 pf ammo. Even with this very light load, I didn't like the jarring and dot movement I got with short stroke. If you're not experiencing any of this , your spring and buffer weight are probably too high.
  7. MM, thanks for the input. I agree with everything you have said. I've been reloading for about 40 years now and your comments are fundamental considerations for doing this safely. I'm not familiar with Prima V but from what I've just learned, it's a very high density powder which performs close to VV N320. I've used a lot of Clays over the years and it is lower density than either of the VV powders but is notoriously hard to meter, especially at low charge weights. I use a lot of n31 and N320 in my Open Steel Challenge loads. The N310 with a MG 95 gr JHP and the N320 with MG 115gr JHP. They are both about 110 PF. The N310 load cycles the slide faster (in a 5" Limcat Steelcat) and will run in almost everything I've tried it in. The 320 load feels softer and won't run in typical bull barrel guns. The light mass of the bushing barrel Steelcat makes it possible to run this load successfully. This is the basis for using N310 powder for this light load experimentation. Probably not the most scientific approach, but based on my experience, the fast burn rate and subsequent high impulse of the N310 gets things moving with light bullets / low powder charges. My guess is that with slower powders there will be a minimum charge weight which allows the gun to cycle that produces a velocity which is higher than I can get with a faster powder. I guess I'm going to have to try this to find out. Good thing I'm retired! :-). As a practical matter, I like the way my PCC runs at 90 PF and will probable stay there. At that velocity ejected cases are clean, indicating that pressure is sufficient to seal in the chamber. While Std Dev is high at 41 fps I'm not concerned with squibs because a 2 sigma velocity variation from the mean would still result in a velocity greater than 800 fps. I am playing with seating the bullet deeper in the case to reduce case volume to see if that reduces the Std Dev, but seating the bullet deeper could itself have an adverse impact on accuracy because of bullet jump from case to rifling. I'm also not concerned with double charges. I'm loading on a Dillon 1050 with Mark 7 drive and think it's nearly impossible to get a double charge with that setup. However, still need to be careful. I hope I'm not coming across as defensive, I really do appreciate the input.
  8. I was on the Wiland website today and noticed that they are advertising the ability of their barrel, bolt and buffer combination to shoot 80 PF ammo. Does anyone know the load data to which they are referring?
  9. I'm actually using more powder than that already in a smaller case. Don't understand why the load you cited would be any safer.
  10. What caliber and bullet weight are the cowboy shooters using?
  11. From Hiperfire troubleshooting page: 4 PROBLEM: Hammer Light Strikes Hammer fall results in light strikes some of the time when using domestic primers but more often on MIL or foreign primers when any of the three toggle spring pairs are installed. The MIL-spec pivot pins supplied with the product are not installed. Instead, the user installs aftermar-ket anti-rotation or anti-walk pins that inhibit free rotation of the hammer in some way because 1) their diameters are greater than 0.154-inches; 2) they do not have a groove to receive the hammer J-spring; 3) they are worn out. REMEDY: Install the FCG with the pins supplied with the product so that the preferred high energy hammer fall is experienced as the baseline. Install other after-market pins only if their impact on perfor-mance does not degrade from the baseline installation. More related to your problem: Trouble Shooting Guide For HIPERTOUCH® Series Triggers www.hiperfire.comPage 4 of 7 underside hits the protruding pistol grip’s attachment screw. 3) Debris is in the FCG cavity (small bits of gravel, blown primer cups, shards of cartridge brass, etc.) preventing the trigger from rotating fully for-ward, because of an obstruction along the trigger’s rear underside. REMEDY: 1) Inspect the lower for dimensional compliance and/or substitute an in-spec lower for instal-lation. 2) Replace the over-long grip screw with a shorter one, or file the end back to eliminate the ob-struction and reinstall. 3) Clean out the large scale debris in the lower’s FCG cavity. 8 PROBLEM: Rifle Doubles Occasionally the rifle will “double,” or after a few thousand rounds, it begins to “double.” 1) The lower receiver pivot pin holes’ dimensional spacing may be out of spec on the high side at man-ufacture, or become high due to excessive wear, causing unreliable retention of the hammer by the dis-connector during hammer cocking (see Figure on previous page). 2) The rifle is not gripped securely by the shooter at the pistol grip causing the hammer to reset during rifle recoil and unintended repeat fire when the rifle then rebounds relative to the more or less stationary trigger finger, commonly called “bump fire.” 3) Over time, because the pull weight is light and smooth, the shooter depends less on conscious and deliberate trigger pull and more on reflexive action where the shooter’s muscle memory contracts the pull stroke length (because it can), which in turn leads to inadequate engagement of the hammer’s secondary sear by the semi-auto disconnector sear causing “bump fire.” 4) The rifle “slam fires” because the bolt carrier group is of the “low mass” variety and/or the recoil buffer spring is too stiff causing high energy inertial collision of the firing pin with the cartridge primer. REMEDY: 1) Inspect the lower for dimensional compliance and/or substitute an in-spec lower for instal-lation. 2) and 3) Grip the pistol grip firmly or install a pistol grip that more completely engages the shooter’s shooting hand, especially when shooting over barricades, weak hand, off bipods, or bags to prevent relative motion of the rifle with respect to the trigger finger; and/or do not stop trigger pull at break, but develop the discipline of deliberately pulling through the break to ensure adequate capture of the hammer by the disconnector; and/or increase the trigger pull weight until “bump fire” ceases. 4) Go back to a stock recoil buffer spring and/or employ a standard-mass BCG and/or use ammunition with harder primers to prevent “slam fire.” 9 PROBLEM: Rifle Bursts Occasionally the rifle will “burst” (unintentional repeat fire beyond two rounds). See Rifle Doubles, where all reasons can apply. REMEDY: See Rifle Doubles, where all remedies can apply. Trouble
  12. This is probably not the problem, but I know that Hiperfife advises against using anti walk pins.
  13. My friend started shooting Atlanta Arms Steel Challenge ammo in his Open gun a couple of years ago. Up to that point I was shooting Montana Gold 115gr JHP over 3.8 gr of N320 in my Steelcats. ( BTW, a very good PCC load, about 109 PF in a 5" barrel.) I took some of the Atlanta apart and identified the bullet as a Berry's 100 gr hollow base 9mm profile set at 1.1"and the powder as VV N310. 3.9 gr. Power factor for this stuff runs at 112 to 118 over my chrono. I decided to use the Montana gold 95 gr JHP to try to duplicate the load and ended up at 4.0 gr of N310 with bullet set at 1.085". This runs at 112 +- PF and cycles my open gun a little faster than the 115/N320 load. It will run in some guns where the N320 will not, probably due to the higher impulse of faster powder. This has proved to be an accurate and reliable load for a couple of years now in temperatures ranging from the 40's to 90's. The MG 95 JHP load wouldn't feed in my PCC so I replaced it with the Berry's 100 gr HB which feeds just fine. Don't exactly recall why I started to experiment with lower powder charges because the 3.8 gr load I started with felt fine to me, It was probably jrdoran's fault . Once on that slippery slope I kept reducing charge weight a couple of tenths at a time until I got the gun to fail at 2.2gr. It ran just fine at 2.5gr with positive cycling and brass ejection, which was amazing to me. I'm in CT so the temperature was around 40F during the testing. My PCC ises a Taccom shrouded barrel, JP bolt and JP SCS buffer with 3 steel and 1 tungsten weight with a green spring. I took samples of the different loads I tried and shot groups from a rest at 17 yards and found the sweet spot at 2.8 gr with groups of about an inch. Maybe an anomaly, but higer and lower charge weights were about double that. I've since verified accuracy at 2.8gr. I think the short distances we shoot Steel Challenge at somewhat mitigates the effects of the high velocity variance we are seeing with the light loads. I agree that 2" groups are terrible but I think they are acceptable for SC given the fact that we never see fliers. For reference, the Atlanta 100 gr SC load we started with has a SD of 12 to 15 fps on my chrono. My 95 gr MG load is about the same. At this point I haven't tested my load with Berry's bullet and 3.8 gr of N310 but I suspect it will be in the same range.
  14. I'm already using Federal small pistol magnum primers.
  15. For comparison, a CCI Minimag is about 50 power factor.
  16. Here's the chrono data from yesterday's testing using Berry's hollow base 100 gr 9mm bullets seated at 1.100" and N310 powder: 10 shot strings. powder chg. avg velocity SD power factor 2.8gr 888 41 89 2.5gr 787 51 79 2.25gr 703 58 70 2.0gr 684 49 68 As noted by perttime, SDs for these light loads are quite high. In spite of this, accuracy at 50' was acceptable for Steel Challenge with sub 2" groups and no fliers noted during accuracy testing. (The 2.8 gr load in my AR shoots sub 1" groups at 50').The most surprising result of this exercise was that our guns would run these loads at all.
  17. Correct, Battle Arms development Sabertube carbine length. They make a rifle length tube also if you want a longer pull. My pull is 11.5" with this one.
  18. Here's the final configuration of my guns. 4# 5 oz for 22 and 5# 1 oz for 9mm. Foam handguards only weigh 0.2 oz.
  19. +1 for Stern Defense. Thousands of rounds trouble free with that system
  20. Agree with this comment. If hammer is falling without marking the primer at all, something, probably the forward face of the extractor, is keeping the bolt face / firing pin far enough away from the the primer so it doesn't mark it. Does the gun still have the standard recoil spring installed? is it in good shape?
  21. This load is probably not good for falling steel but should scrape some paint off Steel Challenge targets OK.
  22. I bought some Berry's 100 gr round nose hollow base bullets to play with. I had previously taken some Atlanta Arms Steel challenge ammo apart and believe that they are using this bullet over 3.9 gr of N310 ai about 1.100" COAL. I started working down a few tenths at a time from that powder charge and ended up at 2.5 gr before my PCC failed to cycle. I'm running a Taccom upper with JP bolt and SCS buffer. To be safe I picked 2.8 gr to run and made a few hundred of them using Fed SPM primers. Surprisingly, my gun cycles very positively and ejects brass 8' or so at this charge. I rested my gun and ran samples from 3.7 gr down to 2.8 gr for accuracy at 50'. 10 shot groups ranged from about 2 3/4" to a little under an inch with the best accuracy at the 2.8 gr load. The 2.8 gr load chrono's at 917 fps avg with a std deviation of 22 fps, so PF = 91.7. My PCC weighs about 5 pounds and feels almost like a 22 with these loads. When I talked with my friend about this he told me that he learned of an even lighter load based on a coated 124 gr bullet which came in at 84 PF. Anyone have experience with loads of this type with a heavier bullet moving at a very low velocity?
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