jimbullet

Is that an STI ejector? The length appears to be normal but I suspect its front face appears to have an angle that I am not sure whether it is correct.

Glad to know that nothing to worry about. I was just making sure I get well within major pf. I had the horrible thought that what if every round went 948fps as I might be doing something wrong and might get stuffed on a match chrono. Thanks guys. Sent from my iPhone using Tapatalk

I did not realise brass has a significant impact on velocities. Yes I do use mixed brass but arent brass just the same in volume/ space? Um, will clean or dirty brass have any significant impact too?

I am wanting to know is there an acceptable fluctuation on the velocities of a pistol cartridge? I am using a Dillon SDB and have in my loads checked the powder charge in every 50 - 70 rounds and they appear to be spot on. OAL I have used for 40S&W is 1.158 however every often when I check with a caliper, it shows up at 1.162, 1.158, 1.160, 1.165. Not sure why its not as consistent as I thought it would be. I checked the seating stem and its fairly tight so its not likely moving on me as after loading 200 rounds recently, I made a dummy round without primer/ powder and checked OAL and it was spot on at 1.158. However randomly checking the loaded ammo, I got the variations. I have been carefully never to short stroke the press as well so I am beginning to think that this might be normal. testing the ammo on the range. The velocities I am getting averages at 958 fps. Unfortunately I was unable to write down each shot but from memory the spreads were a high of 990 fps and a low of 948 fps. Weather was cloudy, overcast temperatures hovering 13-15 deg, feeling like 9 deg. I could remember seeing some muzzle flash on my rounds, shooting at 8am. would appreciate thoughts, your experience.

Ok so I have now extensively tested ammo. I loaded ammo at 1.168 oal and another batch at 1.158 oal. Same projectile at 180 and same powder and powder charge. I initially thought by changing oal the velocity will either increase or decrease however to my surprise there is no change at all. Is it just me or is this normal? I'm thinking of trying 1.190 oal and having the same powder charge and see if there is any change in velocity. Sent from my iPhone using Tapatalk

I wouldn't be too worried about that. As others said, it's a plus minimizing actions you need to do. Sent from my iPhone using Tapatalk

Your load appears quite hot at 8.3 on hs6 and 124. You must be well above PF 170 on that. Is the gun shooting flat though? Sent from my iPhone using Tapatalk

At 11 lbs it would cycle using normal factory rounds so I would think while it is possible to use 11 lbs, the pistol will take heavy beating and I suspect a higher recoil spring weight may be the way to go. Sent from my iPhone using Tapatalk

This would only be half the action though. The dipping forward should just be enough to counter the upward pivot isn't it? I think the better approach I doing some rapid successive live fire and check that your hits on a target say 7 yards away are not making a vertical grouping then you have the correct spring weight. Sent from my iPhone using Tapatalk

Thanks all, At least I can still use the overcrimped rounds to just re-confirm power factor/ velocity with a chrono and then use the properly crimped rounds for actual competition.

My open 2011 pistol used to be a bushing barrel. Gunsmith had it cone comp cutting the slide a bit for the barrel to protrude and attach the comp. Sent from my iPhone using Tapatalk

So I may have stuffed up some loads and its about 60 rounds. I intend to just shoot them for practice instead but was wondering if there should be any cause for concern - i.e. overpressure? Crimped case neck measures at 0.418 on a 40 S&W cartridge. I now know that I should have the crimp at around 0.421 in case neck diameter and have subsequently adjusted to that. The cartridges that I got overcrimped is loaded for major pf. A load that produced a pf 175. Do you think that the pressures could go higher due to the overcrimping? Would it be safe to just shoot it?

I don't clip the spring even with the shok buff on it. Sent from my iPhone using Tapatalk

Wouldn't the round be stopped by the chamber. I'm using a 2011 pistol so should the cartridge get stopped at the barrel hood at its back so it won't over? Sent from my iPhone using Tapatalk

A flat shooting pistol however will help in follow up shots.

I have had very little experience in setting up the crimping die on my dillon SDB. It has been a trial and error on my part and yet I am not absolutely certain whether I have the correct crimp. I am wondering what would go wrong if I had an over crimped cartridge? Does it affect accuracy and or velocity of the bullet? I have heard that an over crimped cartridge could shed off the jacket on a TMJ projectile but I havent noticed that on mine, well from just looking at it that is.

124 gr projectile 7.8 grains hs6 oal 1.13 making PF 168 on my comp'd gun. Sent from my iPhone using Tapatalk

After several test with my current OAL, it appears that it is sometimes hitting the slide stop causing a premature slide lock. I might have to shorten it apparently. Sent from my iPhone using Tapatalk

Using 14 lbs- does it feel like it's slamming the slide rearwards heavily? I have just used the stock recoil spring and at PF 168 it felt like its really pushing the slide rearwards. What PF is your ammo running at when using 14 lb? Sent from my iPhone using Tapatalk

I thought to check with other open glock pistol users as to what recoil spring weight are you using for major pf? Appreciate that the weight of the recoil spring will depend mostly on the load and the number of ports of the comp but I just wanted to get an idea as to what is commonly used. I have a 3 port comp with side ports, using ammo with a pf of 168. So far I have tried the OEM glock 17 recoil spring which from what I have read is supposed to be around 17lbs. So far it cycles. I intend to use a stainless steel guide rod and purchase a suitable recoil spring.

You need to develop a load with a slower powder to achieve a lot of gas behind the projectile to make the comp work resulting to a flat shooting pistol.

My STI mags with the original followers do not do that however I have changed all my followers to grams and bolen and they all have done that without any consequence to feeding reliability.

LegionShooter, I would be interested in what you find (change in velocity) using the two different ammo's (1.215 and 1.180 OAL) of 180 gr projectiles. Interested to see the spreads on yours.

Acceptable is personal - up to you. Depends on how much money you have, and what you're doing with the gun ... Yes, usually in the action matches 2-2.5" at 20 meters is "acceptable", but you can get better - but it's expensive. I actually thought that improved accuracy can be achieved with a variation of a load. As an example, I previously loaded 45acp and the lyman reloading manual indicated a maximum charge and it had a designated the said load as potentially the most accurate. I used the recipe and they were correct as I achieved 1/2 inch groups out at 20 meters with it. Unfortunately, reloading the 40, unlike the 45, throws OAL into the mix and so I am having to throw the reloading book away and experiment. I suppose what I am trying to find is that sweet spot using TMJ projectiles. I previously used lead projectiles with a lower OAL of 1.158 with a pf180 and my pistol was doing 1 inch groups at 20 meters. I am trying to replicate this using TMJ projectiles and had thought that it was as easy as using the same powder charge.

What is an acceptable accuracy on a 40cal out at 20 meters? Should it be less than an inch group? What would make it unacceptable? Reason I am asking is the load I have developed so far with a longer OAL appears loose but not sure if I am just too pedantic about it. The grouping I am getting is 2 - 2 1/2 inches at 20 meters.