achard Posted June 16, 2005 Share Posted June 16, 2005 With my previous load (pf 171) I noticed the burnt powder accumulated more and cost me jammed. I increased .1 grain and the problem solved. Better powder burn. By the way I use VV N320 4.3g Teflon for practice TMJ for competion both 200 grains. oal 1.21" +- Link to comment Share on other sites More sharing options...
cautery Posted June 16, 2005 Share Posted June 16, 2005 .40AET - Just for the heck of it, try loading up a batch to test the following theory: Your ES was reduced when you went to same headstamp... What about if you went to the same headstamp AND made sure all the cases were the same length... Differing case length can change the "effective seating depth"... The base of the bullet ends up in the same place, but the additional length acts as additional "grab" on the side of the bullet.... Cases shorter than "ideal" do just the opposite. I've had "well sorted and culled" brass in a small batch of 100 run from 0.841" all the way up to 0.848". BTW, I proved to myself that .40 brass does IN FACT shrink over time. Additionally, I've seen measurable variation in case wall thickness even within the same headstamp... (different lots?). Thicker case walls act just like longer cases... increasing the total force applied in retension of the projectile. Finally, I used a BUNCH of the MG TMJ... While I liked them fine, IIRC there was a significant weight variation in small samples... on the order of grains rather than tenths of a grain. I weighed and sorted heads for additional consistency. That was years ago though... Yes..... I am very "picky" about certain things. ... some would say about e verything. Link to comment Share on other sites More sharing options...
kevin c Posted June 17, 2005 Share Posted June 17, 2005 The load has always been very accurate. .. <{POST_SNAPBACK}> What about if you went to the same headstamp AND made sure all the cases were the same length... Additionally, I've seen measurable variation in case wall thickness even within the same headstamp... (different lots?). Yes..... I am very "picky" about certain things. ... some would say about e verything. <{POST_SNAPBACK}> Well, I guess I'm picky in the same way. I mostly shoot large lots of once fired brass, all of the same headstamp. This might reduce the inherent variability of mixed headstamp brass or mixed lot/same headstamp brass by quite a lot. But, really, if you're not hugging the power factor floor, and the load is grouping well, does the ES actually mean much, or, for that matter, the SD and AD? Those numbers MAY reflect the inherent accuracy potential of the load by showing greater consistency, but the proof ought to be in the shooting. I gotta confess, though, as a matter of "aesthetics" it tickles me to see those single digits, even though you and I both admit that the accuracy is there regardless. Link to comment Share on other sites More sharing options...
cautery Posted June 17, 2005 Share Posted June 17, 2005 Here's the deal... the vast majority of folks scoff at the idea of ultra-accurate auto-pistols... even in IPSC.... Why? I don't know. Maybe because a lot of the shots are close, big A-zone, etc. OK... Here's the way I look at this whole accuracy thing. Say, and average pistol off-the shelf shoots 2.5" groups from a rest at 25 yards. (IMHO, there are a LOT of unsubstantiated and WAY overstated group sizes being claimed out there). OK, so you are shooting with this pistol... What does a 2.5" group mean? Assume you POA and POI coincide exactly for your pistol. In my book it means that if your point of aim happens to be dead on the A/C line at the break, then you have a 50% chance of claiming a "C". Say, at break, your point of aim is an entire 1" INSIDE the "A" boundary. You STILL have a fairly decent chance of dumping a "C". To "GUARANTEE" an "A" hit with a pistol shooting 2.5" groups, your POA has to be at least 1.25" from any/all "A" boundaries. Look at it another way... With a pistol like this, you are effectively reducing the center A zone from about 420 sq. cm to right at 187 sq. cm..... a whopping 55.4% reduction in target area. Here's a simpler look... A 40 S&W bullet is 0.400". Say you shoot a match and miss winning it (your class or whatever your goal) by the points you would have gotten had you not dropped that last C... That last C fell just outside the A boundary.... It came REALLY close to cutting the line. In this case, had your pistol/ammunition been able to shoot 2.25" groups, that C would have been an A... Anyway... I'm still trying to come up with a "tada" example to demonstrate why super accuracy is a desirable thing in IPSC... A lot of folks are spending big bucks to get that last little bit of.... whatever out of their pistol... reduced muzzle flip, lighter trigger, etc. At some point your dollars per unit improvement ratio gets wayyyy out of whack. I think there are some new (relearned) approaches that will open up some relatively low dollar improvemnts... Some of those are in creating better ammunition... Look at it this way from the ammunition stand point... Say you want to put 2 bullets through the same hole. If ALL pistol and environmental conditions remain the same, then the ONLY non-random way to put teo bullets in the same hole (zero group size) is for the two rounds to be/perform identically. Assuming two rounds are physically identical, the only way for them to travel the same path is to leave the barrel at the same speed and from the same point in space. Shooter controls the point in space... the reloader controls the speed. IDENTICAL ammo, round to round, is realistically impossible, BUT I DO think it is achievable to get reliable/repeatable 10 round group sizes under 1" at 25 yards in a pistol (even a Glock) with a relatively small dollar investment on top of what folks already have in their weapons. Sorry to go so long... It's late; I can't sleep, so I tend to get long winded. Link to comment Share on other sites More sharing options...
Stumpnav Posted June 17, 2005 Share Posted June 17, 2005 As far as clean powders, I've had much better luck with FFFFg over FFg. Link to comment Share on other sites More sharing options...
GuildSF4 Posted June 17, 2005 Share Posted June 17, 2005 Here's a simpler look... A 40 S&W bullet is 0.400". Say you shoot a match and miss winning it (your class or whatever your goal) by the points you would have gotten had you not dropped that last C... That last C fell just outside the A boundary.... It came REALLY close to cutting the line. <{POST_SNAPBACK}> "Thread drift on" It only has to touch, doesn't have to cut. "Thread drift off" Now if the powder is cleaner shouldn't that make the accuracy more consistent since there would be less barrel fouling to affect the bullet? Link to comment Share on other sites More sharing options...
cautery Posted June 17, 2005 Share Posted June 17, 2005 OK, GuildSF4... I stand (semantically) corrected... "Cleaner" powder would/sholud improve accuracy... less fouling of course, but not really significant. IMHO, more importantly, clean burns (read: complete) indicate that you are consistently getting all of the energy out of a given powder charge. In a lot of cases, the "dirt" you see is unburned/partially burned powder, meaning you did NOT get all available energy... This SHOULD show up in inconsistent/"larger" variations in velocity. Link to comment Share on other sites More sharing options...
GuildSF4 Posted June 17, 2005 Share Posted June 17, 2005 Sounds good. Link to comment Share on other sites More sharing options...
kevin c Posted June 22, 2005 Share Posted June 22, 2005 I understand that the old bulleye loads were pretty dirty (not that I ever shot bullseye), but still pretty accurate. Dirty may not be completely burned, but if the same amount of powder burns at the same rate, it might still be fairly consistent stuff. Just random synapses firing between my ears... Link to comment Share on other sites More sharing options...
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