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B_RAD

Case ejection, slide speed, springs and ammo

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Got a couple of questions. I've never had issues with brass ejection until now. I've put an optic on my CO gun and I'm getting brass hitting the edge of the optic. This has got me wondering about slide speed. I've seen others ask about slide speed and ejection but I've never given it much thought. Forgive me if these questions are basic knowledge.

 

1. Will brass eject further if the slide is moving faster?  It makes sense to me that it would. 

 

2. More FPS for the bullet means faster slide traviling rearward? Assuming the same spring is used.  Again, makes sense to me that it would. 

 

3. Does a heavier spring slow the rearward travel allowing more time for brass to clear?

 

4. Does the heavier spring cancelled out number 3 since it also speeds up the forward travel of the slide?

 

 

 

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Posted (edited)

The higher the pressure, most times will have more velocity for a given bullet weight, the faster the slide.

Lowering recoil spring rate will make the slide faster, but can cause feed failures if too light.

Raising recoil spring rate will make the slide slower (and cause the muzzle to dip) at some point causing stove pipes and even failures to feed.

The issue with hitting the optic is not primarily slide speed related, it can be a contributing factor.

The issue will be the ejector or extractor.  You don't say what firearm, my Glock 34's did the same thing and Apex makes a tuned extractor which solved the issue for me.  

Apex also makes parts for other guns also.  Check them out.

In 1911's you can tune the ejector to affect the pattern, don't know if the plastic guns are subject to that though.

Another issue in some instances can be the case hitting the ejection port of the slide, some designs benefit from lowering that port (like 1911's) I've not had to do it with any Glock or the M&P I have.

 

1.  Yes

2. Not always, a lighter bullet at a higher velocity and a lower pf may not have the slide velocity of a heavier bullet at a lower velocity but higher pf.

3. No, reverse is true.

4. Yes, but because it slows the rearward slide speed.

Edited by pskys2

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9 minutes ago, pskys2 said:

The higher the pressure, most times will have more velocity for a given bullet weight, the faster the slide.

Lowering recoil spring rate will make the slide faster, but can cause feed failures if too light.

Raising recoil spring rate will make the slide slower (and cause the muzzle to dip) at some point causing stove pipes and even failures to feed.

The issue with hitting the optic is not primarily slide speed related, it can be a contributing factor.

The issue will be the ejector or extractor.  You don't say what firearm, my Glock 34's did the same thing and Apex makes a tuned extractor which solved the issue for me.  

Apex also makes parts for other guns also.  Check them out.

In 1911's you can tune the ejector to affect the pattern, don't know if the plastic guns are subject to that though.

Another issue in some instances can be the case hitting the ejection port of the slide, some designs benefit from lowering that port (like 1911's) I've not had to do it with any Glock or the M&P I have.

 

1.  Yes

2. Not always, a lighter bullet at a higher velocity and a lower pf may not have the slide velocity of a heavier bullet at a lower velocity but higher pf.

3. No, reverse is true.

4. Yes, but because it slows the rearward slide speed.

It's a G34.  

 

I'm currently using a 11lb Wolff spring.

 

I think it's mostly hitting when using 147 gr ammo around 130 pf. 124 grs around 130 pf seem to be clearing the gun further. 

 

To be clear, your saying that a heavier spring doesn't allow for more time for brass to clear because the heavier spring increases the forward speed?  I'm confused on your answers to questions 3 and 4. 

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reprofile your Glock extractor's hook.

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2 hours ago, B_RAD said:

To be clear, your saying that a heavier spring doesn't allow for more time for brass to clear because the heavier spring increases the forward speed?  I'm confused on your answers to questions 3 and 4. 

 

From slow mo video I've seen the dwell at full slide travel is much longer with the lighter springs.  Therefore it is safe to assume that a lighter spring gets to full slide travel sooner due to increased slide velocity, stays there longer, and returns slower.  

 

In your case, the additional mass from the dot is likely to have created a slightly different ejection dynamic.

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Good luck. 

Brass from my G34 CO gun beats up the optic no matter what you change, do, try, etc... 

 

Springs, diff loads, bullet weights, extractor work, ejector tuning, etc... nothing really fixed it.  I just learned to live with it. 

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1 hour ago, theWacoKid said:

 

From slow mo video I've seen the dwell at full slide travel is much longer with the lighter springs.  Therefore it is safe to assume that a lighter spring gets to full slide travel sooner due to increased slide velocity, stays there longer, and returns slower.  

 

In your case, the additional mass from the dot is likely to have created a slightly different ejection dynamic.

Thanks. I didn't word the questions well. 

 

 

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34 minutes ago, Ssanders224 said:

Good luck. 

Brass from my G34 CO gun beats up the optic no matter what you change, do, try, etc... 

 

Springs, diff loads, bullet weights, extractor work, ejector tuning, etc... nothing really fixed it.  I just learned to live with it. 

Thanks for the input. Guess I'll just get over it. 

 

 

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Posted (edited)
On 8/20/2018 at 10:08 AM, B_RAD said:

It's a G34.  

 

I'm currently using a 11lb Wolff spring.

 

I think it's mostly hitting when using 147 gr ammo around 130 pf. 124 grs around 130 pf seem to be clearing the gun further. 

 

To be clear, your saying that a heavier spring doesn't allow for more time for brass to clear because the heavier spring increases the forward speed?  I'm confused on your answers to questions 3 and 4. 

To clarify a heavier spring does slow the rear momentum of the slide and increases the forward momentum.  But it's a balancing act that has to be made between the springs and the recoil energy.  

Slowing the slide down doesn't help ejection.  Slowing it down can even get to the point where the case doesn't clear the ejection port or worse doesn't allow the ejector to contact the case.  

Since the extractor should hold the case regardless of speed of slide, you need a vigorous rap to clear the case from the port.  Slowing it down changes that, dwell time is not your friend in this instance.  Speeding up the slide will help the case clear the port and the faster the slide the further the case will go.  BUT too light of a recoil spring will batter the frame/slide and can even cause rounds to jump forward out of the magazine, which can also lead to malfunctions.  I like my cases to get thrown about 6 to 8 feet away, but as long as they aren't at my feet I don't stress over that much.

My Glock 34, have both a gen 3 & gen 4 MOS, had a tendency to kick the brass back into my face on occasion.  I was able to ignore it until, like you, it started dinging off of the dot on the gen 3 with an adapter.  So I got the Apex Extractor, problem solved.  When I got the MOS I switched it to that and put the original back in the gen 3 for production.

FWIW I run a 13 lb recoil spring with 145 acme rn coated bullets at 133-135 pf  in my G34's and the gen 3 production has a ss guide rod, the gen 4 mos has an extra long heavy guide rod and a DPP for the optic.  So far the only issues are with me?

Edited by pskys2

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Posted (edited)

The Glock does seem to eject brass sporadically!   

Edited by B_RAD

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I also shoot a Glock 34 in CO and have brass that beats the heck out of my optics. I've changed springs from 11, 13, 15 and different loads. They all beat it up. It has a lifetime warranty so I figure if the glass gets chipped or breaks I will just send it off. 

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