Bottom Edge of Ramp Deforming .40 JHPs.

[Ssanders224]

I was typing that when you posted. And to suggest that you check your mags and springs. Personally, I use Wolff springs cut down to 11 coils. Also check the angle of your followers. They should not be pointing up too high as that can force the top round to exert pressure unevenly on the rear of the case below, dragging it forward.

I changed to all new springs recently and the issue stayed the same. I too wondered if lack of spring pressure was letting the round move too freely.

I use TTIs. I've tried them all, and the TTIs seem to hold up the best for me.

I am going to play around with the mags some more.... But....

I've tried other mags in the gun and they do they same. I've also tried my mags in other guns and saw no issues. So, you see how this gets frustrating ?.

[darkvibe]

Is this the "smiley" shaped mark on the bullets?

Kind of. before I shortened the ramp it was somewhat of a "smiley" i guess.

Now it hits flatter... so not so much.

Sounds like the same thing that I have with a factory STI frame/barrel.

I always attributed it to the top round being stripped out of the magazine pushing the second round forward and then it's hit by the bottom of the feed ramp, just like you said a couple of posts above.

I checked several times and never had any setback and saw other people have it so I just live with it. Figured I would do more damage than good trying to fix it.

[lcs]

What follower in mag?

(1) Over crimping will not prevent setback. Your accuracy will suffer immensely. If you are using Dillon 40 sizing die--get rid of it. Lee U will size the case to just about eliminate setback. Bell is another thing--very little bell is needed for jacketed bullet. I've seen folks expand the entire 40 case by using to much bell.

[Ssanders224]

What follower in mag?

(1) Over crimping will not prevent setback. Your accuracy will suffer immensely. If you are using Dillon 40 sizing die--get rid of it. Lee U will size the case to just about eliminate setback. Bell is another thing--very little bell is needed for jacketed bullet. I've seen folks expand the entire 40 case by using to much bell.

Grams, and/or TTI ( basically the same thing).

Thanks for the input, but there's noting wrong with the affected ammo. It is being subjected to a hit that it's not intended to see. That is the root cause to the setback... Not inadequate case tension.

[lcs]

What follower in mag?

(1) Over crimping will not prevent setback. Your accuracy will suffer immensely. If you are using Dillon 40 sizing die--get rid of it. Lee U will size the case to just about eliminate setback. Bell is another thing--very little bell is needed for jacketed bullet. I've seen folks expand the entire 40 case by using to much bell.

Grams, and/or TTI ( basically the same thing).

Thanks for the input, but there's noting wrong with the affected ammo. It is being subjected to a hit that it's not intended to see. That is the root cause to the setback... Not inadequate case tension.

I agree, but disagree. if you get setback (no matter what initiates the setback), then case tension is suspect.

Sometimes simple things resolve issues. Do all brand name JHP hit the ramp? Do FP mollies exhibit the same behavior? I presume RN would not hit the ramp leaving marks.

[Ssanders224]

What follower in mag?

(1) Over crimping will not prevent setback. Your accuracy will suffer immensely. If you are using Dillon 40 sizing die--get rid of it. Lee U will size the case to just about eliminate setback. Bell is another thing--very little bell is needed for jacketed bullet. I've seen folks expand the entire 40 case by using to much bell.

Grams, and/or TTI ( basically the same thing).

Thanks for the input, but there's noting wrong with the affected ammo. It is being subjected to a hit that it's not intended to see. That is the root cause to the setback... Not inadequate case tension.

I agree, but disagree. if you get setback (no matter what initiates the setback), then case tension is suspect.

Sometimes simple things resolve issues. Do all brand name JHP hit the ramp? Do FP mollies exhibit the same behavior? I presume RN would not hit the ramp leaving marks.

RNFP exhibit the same behavior. PD JHPs are (what I'm running) have a pretty rounded ogive, and it obviously affects them pretty badly.

I'm pretty sure your going to see it on any bullet.

As to the setback, you don't see how hard the nose of some of these bullets is being hit.

It doesn't set back every bullet with the mark.... But some of them show signs of a particularly hard hit, and those tend to be the ones set back.

I have had it happen with Precision Delta long loaded factory ammo... The case tension isn't an issue.

[Ssanders224]

Gonna bump this....

I realize it's a tough one to solve.... Just want to keep it open in case someone has an idea.

[mike cyrwus]

I'd move the whole ramp forward some if it were mine. You look like you have little of the case unsupported and can handle some.

[bthoefer]

Have you polished the disconnector rail? If not you can try this to help eliminate the slide dragging the top round in the mag forward. It's probably not causing your issue but might help.

[CHA-LEE]

Ssanders224> I have experienced the exact same tip of bullet deformation issue. Here is what is causing it...... When the gun fires and the slide cycles back the barrel unlocks and drops down long before the spent case is pulled from the chamber. The bottom edge of the feed ramp slams into the tip of the next bullet to feed while it's still held down slightly by the bottom of the slide.

The only way I was able to fix this was to flatten and move back the bottom edge of the feed ramp so it was even with the frame when the barrel was in the unlocked and back position.

If the bottom of the feed ramp is bashing into the bullet you will have bullet deformation and setback issues. You can try to offset the issue by adding more crimp or under sizing the brass. But that is just treating the symptom verses fixing the root cause. The root cause is to modify the bottom edge of the barrel feed ramp.

If your mags are tuned properly and you are using the proper ammo OAL the bullet tip should be hitting the middle of the feed ramp or a little higher when the round is picked up from the magazine. With this setup you don't even need the bottom portion of the feed ramp so deploying the fix I suggested will not reduce feeding reliability.

[Ssanders224]

Ssanders224> I have experienced the exact same tip of bullet deformation issue. Here is what is causing it...... When the gun fires and the slide cycles back the barrel unlocks and drops down long before the spent case is pulled from the chamber. The bottom edge of the feed ramp slams into the tip of the next bullet to feed while it's still held down slightly by the bottom of the slide.

The only way I was able to fix this was to flatten and move back the bottom edge of the feed ramp so it was even with the frame when the barrel was in the unlocked and back position.

If the bottom of the feed ramp is bashing into the bullet you will have bullet deformation and setback issues. You can try to offset the issue by adding more crimp or under sizing the brass. But that is just treating the symptom verses fixing the root cause. The root cause is to modify the bottom edge of the barrel feed ramp.

If your mags are tuned properly and you are using the proper ammo OAL the bullet tip should be hitting the middle of the feed ramp or a little higher when the round is picked up from the magazine. With this setup you don't even need the bottom portion of the feed ramp so deploying the fix I suggested will not reduce feeding reliability.

Bingo.

Mr. Perez gets it.

What you described is exactly what I've been trying to describe throughout the thread. I've known exactly HOW it happens, I just haven't been able to fix it.

I have shortened the bottom edge of the ramp... to the point that it is even with the frame when the barrel is at full reward travel, but I guess I can try shortening it even more.

As you said, during loading, the rounds hit further up the ramp.

Do you by any chance have a picture of the barrel ramp that you modified?

[CHA-LEE]

I will see if I can take a picture of this tonight and post it up.

I also want to point out that the "softer" the bullets are the more evident this issue will be. For example, I shoot the Rainier Ballistics Plated Bullets and they are a lot softer than copper jacketed bullets. I can see the "Denting" happen with plated bullets where there is zero evidence of it when using copper jacketed bullets such as Zero's. The Montana Gold brass jacketed bullets are even harder so this issue can be really bad and still not show evidence of it on the tips of those bullets.

Since I prefer to shoot the Rainier Plated bullets I have tuned the bottom of the feed ramp to be as flat and smooth as possible so when it does bash into the tip of the bullet it only leaves a small dent in the tip of the bullet. But even then its not causing setback.

[Ssanders224]

Very true.

I shoot only Precision Delta.. usually JHPs, but sometimes FMJs.

It is definitely more evident on the softer JHP tip, but still noticeable on SOME of the fmjs.

One thing I have found, is that I THINK it will setback the FMJs more than the soft JHPs. As in, the tip doesn't deform as much, so there is more force trying to set the bullet back.

[CHA-LEE]

I was able to run home at lunch and take some pictures of the barrel ramp on one of my Limited blasters. As you can see the bottom of the ramp is flattened out and smoothed to blend from the flat to the ramped portion. The barrel in frame picture shows the barrel in the full back and down position. You can even see a little bit of powder build up on the frame just below the ramp where the tip of the "Next" bullet is hitting half of the frame and half of the ramp. I took these pics with my cell phone so they are not the best but I hope this helps solve your issue.

[Ssanders224]

You da man!

Your ramp looks almost exactly like mine does.

mines still hitting.

Guess I'll try shortening it a hair more.

What's so weird is that why some guns do it and some don't?

I tried a buddies the other day (an Akai gun) and could not make the deformed bullet happen.

His ramp is even a little proud of the frame.

[CHA-LEE]

I think that some of it may come down to how high/low the magazine sits in the gun and how much the front edge of the magazine extends upwards to basically block the round from shifting forward while it's in the "Next" position.

[Ssanders224]

Bumping this again.

I have two other Limited guns now... one of which has this issue, and one of which does not.

 

I'm pretty mechanically minded, and pretty good at tuning pistols... but this is crazy.  I can find no rhyme or reason why one gun exhibits this and the other does not.  The areas that you would consider to have an effect are pretty much identical on both guns.  I'm still experiencing too much setback, so I've got to keep diagnosing. 

 

If anyone else has dealt with this let me know. 

[CHA-LEE]

Ssanders224> It sounds like your issue has changed slightly. Is the tip of the bullet still getting deformed? Or is the tip of the bullet not getting beat up but the whole bullet is getting setback in the case?

 

If the whole bullet is getting setback in the case that is sounding like an ammo OAL vs Barrel Feed Ramp depth issue. In all of my Limited guns I had to fine tune the ammo OAL to hit the feed ramp in the correct place to both feed reliably and minimize the chance of setback.

 

The easiest way to check this is to use whatever OAL ammo you currently have on both guns. Use a sharpie marker to black out the whole barrel feed ramp. Then shoot 10 - 15 rounds at a fairly rapid pace. Pull the barrel out and see where on the ramp the sharpie marker is scuffed off. If the OAL is the correct length the marker should be scuffed off at the middle to three quarters the way up the ramp. If the scuff marks are lower than the middle, then the OAL is too short. If the scuff marks are above three quarters then the OAL is too long. 

 

If the OAL is too short the tip of the bullet will hit the very bottom of the ramp first then somewhere higher on the ramp second. This double hit event is what causes setback.

 

Unless your different blasters are built using the exact same brand and type of barrels, there is a good chance that each gun will need a unique OAL to hit the feed ramp in the optimal location. The depth and angle of the feed ramps can be tuned to match each other from one gun to the next. But you will need to set the feed ramp depth and angle to match whatever gun has the deepest one. This is the primary reason why I use the exact same barrel type in all of my guns and tune the feed ramp depth and angle the same across all of them. That way the same ammo can function reliably in all three of my Limited blasters.

 

I doubt that it matters much for your setup but the optimal OAL is 1.165 for my Limited blasters.

[jcc7x7]

On 12/22/2015 at 0:10 AM, CHA-LEE said:

Ssanders224> I have experienced the exact same tip of bullet deformation issue. Here is what is causing it...... When the gun fires and the slide cycles back the barrel unlocks and drops down long before the spent case is pulled from the chamber. The bottom edge of the feed ramp slams into the tip of the next bullet to feed while it's still held down slightly by the bottom of the slide.

The only way I was able to fix this was to flatten and move back the bottom edge of the feed ramp so it was even with the frame when the barrel was in the unlocked and back position.

If the bottom of the feed ramp is bashing into the bullet you will have bullet deformation and setback issues. You can try to offset the issue by adding more crimp or under sizing the brass. But that is just treating the symptom verses fixing the root cause. The root cause is to modify the bottom edge of the barrel feed ramp.

If your mags are tuned properly and you are using the proper ammo OAL the bullet tip should be hitting the middle of the feed ramp or a little higher when the round is picked up from the magazine. With this setup you don't even need the bottom portion of the feed ramp so deploying the fix I suggested will not reduce feeding reliability.

THIS

Several 1911's and 2011's both in 9mm and 40

[Ssanders224]

4 hours ago, CHA-LEE said:

Ssanders224> It sounds like your issue has changed slightly. Is the tip of the bullet still getting deformed? Or is the tip of the bullet not getting beat up but the whole bullet is getting setback in the case?

 

If the whole bullet is getting setback in the case that is sounding like an ammo OAL vs Barrel Feed Ramp depth issue. In all of my Limited guns I had to fine tune the ammo OAL to hit the feed ramp in the correct place to both feed reliably and minimize the chance of setback.

 

The easiest way to check this is to use whatever OAL ammo you currently have on both guns. Use a sharpie marker to black out the whole barrel feed ramp. Then shoot 10 - 15 rounds at a fairly rapid pace. Pull the barrel out and see where on the ramp the sharpie marker is scuffed off. If the OAL is the correct length the marker should be scuffed off at the middle to three quarters the way up the ramp. If the scuff marks are lower than the middle, then the OAL is too short. If the scuff marks are above three quarters then the OAL is too long. 

 

If the OAL is too short the tip of the bullet will hit the very bottom of the ramp first then somewhere higher on the ramp second. This double hit event is what causes setback.

 

Unless your different blasters are built using the exact same brand and type of barrels, there is a good chance that each gun will need a unique OAL to hit the feed ramp in the optimal location. The depth and angle of the feed ramps can be tuned to match each other from one gun to the next. But you will need to set the feed ramp depth and angle to match whatever gun has the deepest one. This is the primary reason why I use the exact same barrel type in all of my guns and tune the feed ramp depth and angle the same across all of them. That way the same ammo can function reliably in all three of my Limited blasters.

 

I doubt that it matters much for your setup but the optimal OAL is 1.165 for my Limited blasters.

 

Charlie,

 

Na same issue.

i just tried to ignore it for a while, but it's on my mind again.  I went out to check my load for this year, and it shows up in velocities.  It causes inconsistent velocities sometimes when the bullet gets setback.

 

the nose of the bullet gets deformed, and some of them get set back.  

 

OAL isn't an issue, and I have schuemanns in all the guns.

problem happens with any length ammo. 

 

Im going to trim back the ramp on the other gun with the issue and see what happens..... BUT, the weird part is that on the gun that does NOT have the issue the feed ramp definitely protrudes past the frame.  So idk what to think. 

[Ssanders224]

I cut the ramp back.

if anything, it screws up the nose of the bullet worse now.

awesome. 

 

[Ssanders224]

Here you can see where the round makes contact. 

The two lines on the bottom of the ramp are the edges of the hollow point. 

 

[tyler2you]

It's definitely a frustrating issue.  I cut my ramp back completely flush with the frame and I still get some deformation.  The deformation is flatter now versus the sharp crease that I was getting before cutting it back.  When I talked to Matt Cheely about it he said that it was pretty common and that he had the same issue with his personal gun. 

 

I gave up on trying to fix it and started using the Lee undersized die to hopefully give me some more tension to guard against setback.

[Ssanders224]

Just now, tyler2you said:

It's definitely a frustrating issue.  I cut my ramp back completely flush with the frame and I still get some deformation.  The deformation is flatter now versus the sharp crease that I was getting before cutting it back.  When I talked to Matt Cheely about it he said that it was pretty common and that he had the same issue with his personal gun. 

 

I gave up on trying to fix it and started using the Lee undersized die to hopefully give me some more tension to guard against setback.

 

Yea, I'm about to that point. 

The issue is that our mags let the top round sit so high in the frame that the nose is behind the ramp... instead of fully/partially down behind the frame. 

The round is inevitably going to slide forward some, so when the barrel comes back it pops the nose of the bullet.

If the round sat low enough to be partially behind the frame, this wouldn't happen.  

 

I don't know that there is a way to fix it.... which sucks. 

Even with undersized neck tension, and a good crimp, I still have a few setback far enough to spike velocity by 50-60 fps.  Not cool. 

[CHA-LEE]

What brand of magazines are you using?