Optic + Rail Weight - How Much is Too Much?

I was watching a thread here about a guy looking for a new rail to mount on his Range Officer, and some of the responses by both advanced shooters and pistol smiths got me wondering if there is a known range of acceptability when it comes to weight on your slide and reliability. For instance, I have a Range Officer with a Matchdot II and a Marvel steel rib. The total weight of all of that hardware is 9 or 10 ounces. I'm using an 11lbs recoil spring and 4.8 grains of HP-38. This combo is both accurate and as reliable as I have found without raising the powder level too high. If I drop the powder down to 4.5 or 4.6 grains, the shells don't eject consistently and will cause a malfunction. If I drop the recoil spring down to 9 pounds with any load, the slide won't go back into full battery every time with SWC bullets - even with a throated barrel, thus causing a malfunction. If I raise the recoil spring weight to 13 pounds, even with 4.8 grains of powder, the shells won't eject properly, but the gun will go back into battery more easily. With the setup I'm at currently, I will get a malfunction about 1 every 100 rounds. Is that an acceptable, common, or standard malfunction rate? Obviously when that malfunction comes up, it costs me an alibi. 

Hypothetically, if I switch to an aluminum rail (I hate working with aluminum, by the way) and an Aimpoint, I'll bet I would shave at least 5 ounces off my slide weight, which would invariably make the gun less finicky, and allow for more margin of error with the slide weight/recoil spring/feed angle combination. 

I just recently helped my dad mount a steel RRA bullseye rib w/adjustable rear sight to his Range Officer to try and get him setup for bullseye competition with me, but with his rail (6 ounces) his setup will be an extra ounce or two even heavier than mine. Now I'm wondering if I steered him in the wrong direction. Any opinions on this?

thanks,

Dave

Look at the AMU....huge ass scope aimpoint 9000sc slide mounted, KC does his intergal cut for micros, Keefer & Sams are big fan of frame mount.

A properly setup gun & ammo will work correctly.  Now each one of those mounting options will require different springs and loads. I would  rather a lighter optics setup or stouter load than to have to skimp on lockup and fitting.

Some shooters prefer the feel of a slide mount over a frame.

I run a slide that has been lightened a lot with the help of from Jon and KC work. I also run light loads people say are to light.

That is huge scope. I love KC's integral cut for those micros. Definitely a bigger fan of doing all my own pistol work, within my limits...I figured this out after my local pistol smith quoted me $125 and 6-8 weeks wait time to drill and tap a rail the first time I looked into getting that job done. I guess tinkering with the lips on the magazines to alter the feed angle may improve reliability - I think what I got from your post, is that a 1/100 malfunction rate is not acceptable, lol.

daflorc wrote:That is huge scope. I love KC's integral cut for those micros. Definitely a bigger fan of doing all my own pistol work, within my limits...I figured this out after my local pistol smith quoted me $125 and 6-8 weeks wait time to drill and tap a rail the first time I looked into getting that job done. I guess tinkering with the lips on the magazines to alter the feed angle may improve reliability - I think what I got from your post, is that a 1/100 malfunction rate is not acceptable, lol.

Amu runs factory ammo I believe so that's how they get those to run.  Let's say your set to win the national championship. And you get 4 away before an alibi so you take your alibi and get the other five off.  Now you have to take the low 10 of your 14 shots.  Could be a loss by X count or points as we know no one has ever fired a perfect 2700

Yeah, that's a good point.

daflorc wrote: With the setup I'm at currently, I will get a malfunction about 1 every 100 rounds. Is that an acceptable, common, or standard malfunction rate? 

No, an acceptable malfunction rate is zero.  You can only lose points on an alibi, and once you've used one it changes your focus. Instead of focusing on fundamentals, you're thinking, "what am I going to do if this thing chokes again?"

rreid wrote:

daflorc wrote: With the setup I'm at currently, I will get a malfunction about 1 every 100 rounds. Is that an acceptable, common, or standard malfunction rate? 

No, an acceptable malfunction rate is zero.  You can only lose points on an alibi, and once you've used one it changes your focus. Instead of focusing on fundamentals, you're thinking, "what am I going to do if this thing chokes again?"

I guess I need to figure out the issue my gun has.

I don't want to go into the slide mount vs frame mount issue. If interested check a few old forums there is a lot of ford/chevy chatter. Any alibi is one to many and should be looked into. Included is the shooter too. Being that the gun is held in one hand without support the shooter becomes part of the guns function. Yes the AMU is using factory because they don't reload pistol ammo however do buy a custom load from Atlanta Arms that are not as hot as typical 185gr factory. Adding the 9000SC to the gun did not change the ammo requirement, they use the same long line load they had when using the Aimpoint micro. However they did have a short line load that is now only used by those shooters without the 9000SC (new shooters) The issue was that the short line load did work from a rest and most of the time by the shooter but if for any reason the shooter got a little variation in his hold it created a malfunction. I'm sure that short line load being near the minimum requirement the gun needed to function properly there may have been some alibis caused by the gun too. One indication of possible shooter error is the malfunction only happens during timed or rapid fire and never is slow. Granted the shooter will shoot twice the amount timed and rapid as compared to slow fire. However the shooter is much more aware of what he is doing during slow.

Froneck wrote:I don't want to go into the slide mount vs frame mount issue. If interested check a few old forums there is a lot of ford/chevy chatter. Any alibi is one to many and should be looked into. Included is the shooter too. Being that the gun is held in one hand without support the shooter becomes part of the guns function. Yes the AMU is using factory because they don't reload pistol ammo however do buy a custom load from Atlanta Arms that are not as hot as typical 185gr factory. Adding the 9000SC to the gun did not change the ammo requirement, they use the same long line load they had when using the Aimpoint micro. However they did have a short line load that is now only used by those shooters without the 9000SC (new shooters) The issue was that the short line load did work from a rest and most of the time by the shooter but if for any reason the shooter got a little variation in his hold it created a malfunction. I'm sure that short line load being near the minimum requirement the gun needed to function properly there may have been some alibis caused by the gun too. One indication of possible shooter error is the malfunction only happens during timed or rapid fire and never is slow. Granted the shooter will shoot twice the amount timed and rapid as compared to slow fire. However the shooter is much more aware of what he is doing during slow.

Thanks for the info, I lost an EIC match because of my light loads once... last string of rapid fire my grip changed just ever so slightly causing an alibi, followed by another alibi cause i was worried about the alibi.  Jut prior to the EIC match i shot my "ball gun" for the 45 portion of the 2700 without any malfunctions.

keep the strongest recoil spring that closes the slide quick and tight then start bumping up your powder a tenth at a time till you get 100% function, or if using a light crimp say .470 or up tighten it down to .468, either way you will get it working fine without spending big bucks changing rails or dots. Also could switch to a hotter powder like bullseye or tightgroup.

DavidR wrote:keep the strongest recoil spring that closes the slide quick and tight then start bumping up your powder a tenth at a time till you get 100% function, or if using a light crimp say .470 or up tighten it down to .468, either way you will get it working fine without spending big bucks changing rails or dots. Also could switch to a hotter powder like bullseye or tightgroup.

This is helpful - 4.8 grains of HP-38 is a pretty stout load, I'd rather not bump it up more if I can help it. A 9lbs recoil spring is too light I've found, and a 14lbs is too heavy - currently I'm at an 11lbs spring which causes a malfunction 1 out of 100, on average. I have been using a .470 crimp. Possibly a .468 crimp combined with a 12lbs spring might do the trick? The malfunction isn't occurring with ejected shells, it is a live round not feeding into the barrel completely, as if it needs more power to force it in. I've already throated the barrel, and I've been wondering if rounding out the top of the ramp a little more would also help, but I have not found any information about the possible consequences of an over-throated barrel.

I think I'll eventually try a hotter powder, but I have 8 pounds of HP-38 to run through first

When you say the round is not feeding into the barrel completely, How much is not completely? When letting the slide go forward slowly with no rounds in the magazine nor one being chambered (empty gun) does the slide close smooth with out any noticeable bump or restriction?

be sure you don't have excessive extractor tension.. Too much will cause you feed issues... also the profile of the extractor can help or hurt..

Froneck wrote:When you say the round is not feeding into the barrel completely, How much is not completely? When letting the slide go forward slowly with no rounds in the magazine nor one being chambered (empty gun) does the slide close smooth with out any noticeable bump or restriction?

The slide closes smoothly without any rounds in the magazine. By not completely feeding, I mean that the round will go into the chamber halfway, and get stuck at an upward angle, requiring me to bump the slide to get it to seat properly and close the slide completely.

jglenn21 wrote:be sure you don't have excessive extractor tension.. Too much will cause you feed issues... also the profile of the extractor can help or hurt..

I did not think of this - I actually just added tension to that extractor because I thought it was too loose. I may have overdone it. I need to check, thanks for the tip.

Very interesting thread, I have a similar pistol setup and had to replace the extractor (a bulleye pistol smith did this not yours truly) and now I am having trouble with case extraction.  Using the same load as this poster is using (powder charge that is) so I will be interested to see how his problems play out.

So recapping what you have, the slide closes very smooth with no ammo in the gun yet when a load is attempting to chamber letting the slide close slooowly with the hand holding the slide it will stop about 1/2 way. When shooting the gun you get about 1 in 100 that does stop the slide from closing when allowed to cycle normally. I assume the round stopping the cycle is 1/2 way in.
 One quick check will be to remove the extractor and try chambering a round. Since your reloading I would suggest if not already done is to make a few dummy rounds without replacing the used primer and no powder the exact same as your loading.
 Also does this problem exist with a full magazine? First round, second etc. All rounds? I also assume you checked your reloads and the primer is at least flush with the case.

Froneck wrote:So recapping what you have, the slide closes very smooth with no ammo in the gun yet when a load is attempting to chamber letting the slide close slooowly with the hand holding the slide it will stop about 1/2 way. When shooting the gun you get about 1 in 100 that does stop the slide from closing when allowed to cycle normally. I assume the round stopping the cycle is 1/2 way in.
 One quick check will be to remove the extractor and try chambering a round. Since your reloading I would suggest if not already done is to make a few dummy rounds without replacing the used primer and no powder the exact same as your loading.
 Also does this problem exist with a full magazine? First round, second etc. All rounds? I also assume you checked your reloads and the primer is at least flush with the case.

This is correct, and the problem will occur randomly. My last alibi due to this issue was the 2nd of 5 rounds failing to chamber correctly. All rounds fit into the SAMMI gauge and the primers are flush with the case. I think creating some dummy rounds with these SWC and really looking closely at what is happening on a slow hand closed chamber is a good idea. I'll be checking extractor tension as well. Good advice.

Do all rounds plunk test properly in your chamber?  I have a SA RO 9mm that the chamber is really tight and many rounds dont plunk test.  They go into the SAMMI tester gage just fine and feed in my other 9mm fine but many have to be ran through a bulge Buster Die before the RO will eat them.  Don

Good point, make sure your loads pass the plunk test. If they do Check the entry point into the extractor. If your saying that it has some resistance to chambering every time you let the slide go forward slowly holding the slide in the hand, remove the extractor and see if it disappears. May not be extractor tension but the lead into the extractor may be sharp.

Magload wrote:Do all rounds plunk test properly in your chamber?  I have a SA RO 9mm that the chamber is really tight and many rounds dont plunk test.  They go into the SAMMI tester gage just fine and feed in my other 9mm fine but many have to be ran through a bulge Buster Die before the RO will eat them.  Don

My chamber isn't particularly tight at all - I also use the lee crimp and resize die as the last die in my progression on my Dillon 650. I've got maybe 10,000 rounds through this gun, and I was using hardball with a 14lbs spring all the way up until a couple months ago. Everything ran flawlessly with the heavier spring. Now I bring my spring weight down to accommodate the light reloads, and that is when the issues began.

Froneck wrote:Good point, make sure your loads pass the plunk test. If they do Check the entry point into the extractor. If your saying that it has some resistance to chambering every time you let the slide go forward slowly holding the slide in the hand, remove the extractor and see if it disappears. May not be extractor tension but the lead into the extractor may be sharp.

As soon as I get back from vacation, I'm definitely going to check the extractor, and cycle it without, to see what's going on. I'm waiting on a new gun for the long line, and I'm going to put the Matchdot II I have on this Range Officer onto the other gun, and replace it with a 25mm ultradot, since I'm only going to use this gun for the short line. I figure the 1oz. reduction in weight of the smaller optic plus a 1lbs heavier recoil spring would benefit the cycling of the rounds.

Try different magazines sometimes it's as simple as that

Dave is right . Try different style  mags that have the 3 different style feed lips.  Try the smoothest style.

What are the 3 different mag styles? I replaced the stock steel followers with Wilsons which are some sort of plastic awhile back.