cautery Posted October 19, 2005 Share Posted October 19, 2005 (edited) Continuning my work in designing G-35 barrels... I received Proto #3 over the weekend, and it looks very promising. I will be running a series of chrono/grouping tests tomorrow, and will write/post a full report as soon as I can. But as a preview, here is what I plan to do tomorrow: 1) Go to range with chrono, Ransom Rest, and about 8 different test loads (actually, it's my "stock" reloads, and a serires of 7 "semi-match" loads varying only in powder charge). 2) I am going to chrono all eight ammunition loads through a) Glock stock barrel, 2) Aftermarket stock "drop-in" stainless barrel, and 3) Proto #3 (same base barrel as #2 above, but with my chamber and headspacing design). 3) At the same time I chrono the loads, I will be collecting grouping targets on each load per barrel to use in analysis along with the chrono printouts. (Then I am going to re-zero my weapon with Proto #3 and my chosen match load... and then practice if there is enough daylight left.) Proto #3 has a "shorter than SAAMI" spec for the headspacing (headspacing shoulder to barrel hood), a VERY short lead, and a "standard" throat angle. This allowed me to select a sample of same headstamp brass, and trim it all to an approximate 0.001" headspacing. My only concern at this point is that the finish reamer I used was designed when I was using MG 180g CMJ bullets. I am now using PD 180gr FMJ. The PD bullet (as most other also do) has a different profile than the MG bullet. Since I am using a Redding Competition Seating die (micrometer), the bullet seating insert indexes on the bullet profile rather than the flat tip (not a bad thing BTW...) Switching to the PD bullet and using the reamer cut for the MG bullet results in a zero bullet jump at approx. 1.120" rather than the 1.1301" for the MG bullet. Thus, I am having to load the test rounds down to 1.119"... not a bad thing (w/ VV N-340 anyway), just different. Because of this, I have backed off to 5.3gr starting load to make sure at least one loading falls below Major (and to make sure pressure isn't an issue). Now, the test tomorrow has several goals, but the primary one is to "re-validate" the "near zero bullet jump" theory with this new barrel. Secondly, I want to find out if the shorter OAL (deeper seat) will cause pressure problems at max load (6.0gr), thus I am stepping up from 5.3 to 6.0 by 0.1gr increments. Ancilliary goals are to get a better idea where the most consistent load is as relates to powder charge vs. chrono/grouping results. Additionally, I am shooting "stock" reloads against "semi-match" loads to test the close headspacing theory. The stock reloads are random case length (as sized) all within/under SAAMI specs. Some much shorter than the chamber, some right at chamber length (I've culled the few that are above chamber length for safety reasons). It is my hope that I can validate my theory that consistent case length, close headspacing, and hence consistent location of round in chamber will deliver more consistent (hopefully smaller) groups than the "stock" reloads. As long as nothing unexpected happens on this series of tests, I plan to order a new finish reamer cut to match the Precision Delta bullet profile, allowing longer OALs (out to the max magazine capacity), while maintaing near zero jump. this is so that I can start this whole exercise over using VV N-320 and/or Tightgroup (which are the two candidates for next season's powder order). I am also trying to get a full sample collection of MG and Zero .40 S&W bullets in JHP, FMJ and all weight ranges to compare profiles to determine if the two finish reamers will accomodate all of them, or if I will need a 3rd/4th to complete the set. Stay tuned... Edited November 10, 2009 by Flexmoney Link to comment Share on other sites More sharing options...
Flexmoney Posted October 19, 2005 Share Posted October 19, 2005 Any chance that the new barrel will need some "break-in"? Link to comment Share on other sites More sharing options...
cautery Posted October 19, 2005 Author Share Posted October 19, 2005 Who knows... What do you think? I could practice first, then clean it, then test... I was going to d about 300 rounds in practice tomorrow... Link to comment Share on other sites More sharing options...
Flexmoney Posted October 19, 2005 Share Posted October 19, 2005 I don't know...maybe ought to ask those precision rifle guys? Heck, give it a go, see if it works. If no, shoot it some more to polish it up. Any excuse to shoot more. Link to comment Share on other sites More sharing options...
cautery Posted October 19, 2005 Author Share Posted October 19, 2005 I don't remember breaking in Proto #1 (or Proto #2 for that matter). Be glad when I get al this "drop-in" testing done... I really want to get an oversized barrel that hasn't been finish reamed (or rough remaed too deep for my finshed chamber specs). I want to see what happens when the jump/headspace stuff is combined with a barrel that is located in the same place for every shot with respect to the sights. Link to comment Share on other sites More sharing options...
cautery Posted November 4, 2005 Author Share Posted November 4, 2005 OK... Here's an update. I scrapped the scheduled test due to a couple of factors: 1) Couldn't get the chrono to work reliably, and 2) It was bothering me that I couldn't load any longer than 1.119" or so using the PD bullets with my prototype barrel. Well, I got my shipment of Montana Gold 180gr. FMJ today... And just as I figured, I can load much longer with them. In fact, I can load to right at 1.154" with zero rifling contact (using the drop and spin method). Of course, I can't load more than 1.150" max in my mags without having problems, so I'll have a little more than 0.004" jump... but that's a lot less than the 0.105" jump on a stock barrel. As soon as I get some spare time, I'll get back to testing on this... Link to comment Share on other sites More sharing options...
Kevin Kline Posted November 4, 2005 Share Posted November 4, 2005 I finally got to shoot my G20 KKM .40 caliber barrel yesterday. It shot flawless with no malfunctions. It was also pretty accurate as well. I got the drop in and it shot very accurate, especially since I still have the crappy stock sights on it. Flex, you're definitely right about shooting the G20 in LImited/Lim 10 instead of the 35 or smaller frame Glocks. The G20 handles the recoil better and now after shooting the KKM barrel in it, it's even better. I havent even done anything to it, it's completely stock, except the KKM barrel. I haven't added a trigger job, good sights or magwell to add weight. Im going to get it ready though. Its just a little different shooting the large frame, then switching to small frame for Production. Link to comment Share on other sites More sharing options...
Flexmoney Posted November 4, 2005 Share Posted November 4, 2005 Kevin, It does seem to be the sneaky cheater gun. I do grip it differently though...and tend to want to push shoots off (to the right for me). I hope I don't talk you into to doing so. I think it is because I have so much time burned in behind my regular framed Glocks. OK...back to Clay's barrel... Clay, that 0.004 clearance has got to be as close as you'd want to run? I don't know how tight the rifle guys get, but 0.004 seems small... **It might be important to point out again (for others) that you are running brass that you have taken extra measures to ensure it is exact in size. And, that your press has been tweaked to produce ammo to a tight tolerance in OAL, as well. ** On your OAL for mag function, make sure to run with full mags (for testing). In my Open 9 glock, I like a longer OAL. But, I had to bring it in some, as the mags would run fine with a few rounds in them, but not when full. Link to comment Share on other sites More sharing options...
cautery Posted November 4, 2005 Author Share Posted November 4, 2005 (edited) Flex... ALL good points... Here, let's put the proper warnings in. 1) You probably don't want to try this one at home kiddies!!! 2) Reducing bullet jump results in placing your bullet VERY close to the rifling. If you screw up... AT ALL when you have clearances in the low thousandths, you can have BIG problems in a hurry... 3) IT IS POSSIBLE/PROBABLE that you can have major pressure spikes that could rupture the case and/or blow the barrel up if you screw up. 4) You MUST use good brass that is properly trimmed to within 0.001" of each other if you are going to monkey with setting headspacing to close tolerance. Brass can often vary by over 0.010" from case to case even after resizing. When you are talking about setting headspace around 10-20% of that, you can see the futility and the possible problems it could cause. 5) You MUST, MUST, MUST either spend a zillion hours like I did to get my progressive press capable of producing OALs (and with trimmed brass = seating depth) consistently to within 0.001" OR use a GOOD single stage press to seat the bullets. 6) You ABSOLUTELY MUST measure and chamber check EVERY ROUND! Failure to follow the above and a bunch of other stuff may well result in damage or death to you, damage to your stuff, or at least a malfunctioning pistol. Edited November 4, 2005 by cautery Link to comment Share on other sites More sharing options...
cautery Posted November 4, 2005 Author Share Posted November 4, 2005 Flex, On the jump spec of 0.004". Yeah, that's getting down there in the near minimum range. A lot of factors here to consider... If the bullet tips in the 0.003" or so sidewall clearance in the chamber, will the bullet touch? Yep, the best way here is to do the tilt and spin test to see if you can feel it drag while you tilt the bullet to the side of the chamber and twist it in a full 360 degrees... Once I get back to a good foundation to work from, maybe I'll do some testing with jump as the only variable.... 0.004" to say 0.020" by every 0.002 " or so... see if it has an impact down that far... I believe there will be a tradeoff between accuracy and jump distance... I also think there will be a point of diminishing returns down around 0.010"... but I may be way off. There IS one... just gotta plot the curve and pick it out. Link to comment Share on other sites More sharing options...
Flexmoney Posted November 4, 2005 Share Posted November 4, 2005 Plotting the curve would be great. Link to comment Share on other sites More sharing options...
Joe D Posted November 5, 2005 Share Posted November 5, 2005 Clay, you have too much time on your hands. Do you have a life? Link to comment Share on other sites More sharing options...
cautery Posted November 5, 2005 Author Share Posted November 5, 2005 Flex, I plotted the curve on my stock G22 trigger... The plot is VERY instructive... Shows where all the glitches and hitches are... Gives you a good tool to use when tuning... helps diagnose what's causing what throughout the pull. Joe D - LOL! I have a life NOW that I'm rid of the 105lbs of bad news out there in California. Nah, not enough time really. I need about 8 more hours a day to get done what I want done in the time frame I need it done. It's tweekers like me that make all the cool discoveries... About 1 in 100 projects at last check turn out to be something pretty cool. Link to comment Share on other sites More sharing options...
Joe D Posted November 5, 2005 Share Posted November 5, 2005 I too am a tweeker. Some of us came up with the "Vanek Trigger" mod before he did. A 1 lb. Glock trigger is not too hard to do. As you can tell from my posts I am a fan of the stock Glock barrels. My wife's G34 has put five shots into a group, at 25 yds., that could be covered by a nickel. I wish I could find that target again. I do have several witnesses that saw me shoot it though. Most shooters don't take the time to properly work up loads. I guess I don't get too hung up on trying to get those sub 1" groups. The target we shoot at is huge. Both of my G35s will group under 1 1/2" with stock barrels. Link to comment Share on other sites More sharing options...
eric nielsen Posted November 5, 2005 Share Posted November 5, 2005 +1 I've shot sub-1" groups - frequently - with the stock G35 barrel. Zero 180JHPs and Titegroup. Link to comment Share on other sites More sharing options...
glockrocker Posted November 6, 2005 Share Posted November 6, 2005 (edited) I too am a tweeker. Some of us came up with the "Vanek Trigger" mod before he did. Hi Joe D. Not that it really matters, but when did you come up with the "Vanek Trigger" mod and how long was it before Charlie developed it? How is it that you are aware of the date that the Vanek trigger was originally developed by Vanek Custom? Just curious... Edited November 6, 2005 by glockrocker Link to comment Share on other sites More sharing options...
Flexmoney Posted November 6, 2005 Share Posted November 6, 2005 Lets get back on topic, please. We can leave the chicken vs. the egg type (which came first) debates for GlockTalk. Link to comment Share on other sites More sharing options...
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