Rethinking 460 Rowland suppressed

[Hannibalbarca]

So I had wanted to do a pistol braced Glock 21 build.
It would be a Glock 21 gen 3 non sf
Stock adapter with sb15 Bruce original
Tritium fiber optic suppressor night sights
Extended mags
24lb ismi spring
Stainless guide rod
Silencerco 5.25 threaded barrel or a wolf 6.61 barrel
a plastic buffer that’s put in the frame
And a form 1 suppressor using the aj guns booster. Will weigh just under 28 oz and have quite a bit of blow black due to the first baffle being very close.
I’d like to use hot loads, 250 at 1200-1300 FPS. This would actually be 45 super brass or 45 smc brass loaded to 460 Rowland specs.
The problem is that the slide has to remain in position to achieve safe pressures, this is done with a muzzle brake. I wanted to use a suppressor but it seems that the booster is so good at disengaging the weight of the suppressor that it won’t do anything to slide unlocking time. I was thinking of not using a booster but then I would imagine it would just be semi auto.

For anyone here that shoots 45 super or 460 Rowland, have you tried suppressing it? Am I incorrect about the slide not being delayed by the suppressor?

[ECCO Machine]

For anyone here that shoots 45 super or 460 Rowland, have you tried suppressing it? Am I incorrect about the slide not being delayed by the suppressor?

They're all delayed a bit on short recoil handguns; the inertia of the piston and spring soak up some of the available energy. Enough to let pressures drop to safe levels with hot loads in a modified gun? Only one way to find out.

Muzzle brakes (unless they're exceptionally heavy) and recoil springs do virtually nothing to delay slide unlock. The former reduces felt recoil and muzzle climb, the latter slows the slide down during recoil and returns it to battery. Spring weight can affect cycling, but not unlocking. .45 ACP has 3,700 lbs of bolt thrust; increasing spring compression weight by a few pounds does nothing to counter that.

What you could do to slow it down if needed is a stouter spring in the booster, which will increase inertia by reducing the decoupling effect of the booster, forcing the slide & barrel to carry more of the suppressor's mass with them.

I’d like to use hot loads, 250 at 1200-1300 FPS. This would actually be 45 super brass or 45 smc brass loaded to 460 Rowland specs.

The suppressor will take the edge off, but, like 10mm, it's still gonna be too much for naked ears. No reasonably sized suppressor, production or my own, has taken my 1,400 FPS 180 gr. 10mm loads down to a level that I find tolerable to my ears.

[yondering]

ECCO, that is completely false about muzzle brakes. They absolutely do delay slide unlocking, and in fact a good brake is the only way to safely push that kind of power level out of a Glock. Watch some slo-mo video, you'll see the bullet leave the barrel and the gas acting on the brake before the slide moves.

Heavier recoil springs don't do a lot for delaying unlocking, but they do contribute a little bit in a striker fired pistol, and a heavier spring is highly recommended for hot Glock loads.

To the OP - depending on the weight of your can, you might get away with no booster, but I'd plan for one and use a solid spacer instead of the spring at first. If it doesn't cycle, experiment with very heavy springs. You do not want a standard weight booster spring (as would be used for normal 45 ACP), you'd be asking for a case rupture. If you experiment with this, do it one round at a time with the magazine removed, so the gas can escape if you experience a rupture.

[Hannibalbarca]

ECCO, that is completely false about muzzle brakes. They absolutely do delay slide unlocking, and in fact a good brake is the only way to safely push that kind of power level out of a Glock. Watch some slo-mo video, you'll see the bullet leave the barrel and the gas acting on the brake before the slide moves.

Heavier recoil springs don't do a lot for delaying unlocking, but they do contribute a little bit in a striker fired pistol, and a heavier spring is highly recommended for hot Glock loads.

To the OP - depending on the weight of your can, you might get away with no booster, but I'd plan for one and use a solid spacer instead of the spring at first. If it doesn't cycle, experiment with very heavy springs. You do not want a standard weight booster spring (as would be used for normal 45 ACP), you'd be asking for a case rupture. If you experiment with this, do it one round at a time with the magazine removed, so the gas can escape if you experience a rupture.

It weighs 28 oz with the booster. 20.5 without.
Where could I get more stouter springs for the booster?

[yondering]

Dang that's pretty heavy with the booster, I'm sure you'll need some sort of spring to cycle that. McMaster has a good selection of springs. Along with length and diameter of the spring, you need to pay attention to wire diameter and number of coils. Larger diameter wire or fewer coils = higher spring rate. The static compressed load of the spring inside the booster is the critical detail, so you'll need to do some measuring and a little engineering.

Or you could go the other way- use the spring you've got and work up your loads until you find the max that setup will handle. Watch for smileys or rings around the case heads and of course any other pressure signs too. Extractor marks (bent or torn rims especially) are another sign of early unlocking under high pressure, and ejection distance is a useful thing to watch as well.

[Hannibalbarca]

Dang that's pretty heavy with the booster, I'm sure you'll need some sort of spring to cycle that. McMaster has a good selection of springs. Along with length and diameter of the spring, you need to pay attention to wire diameter and number of coils. Larger diameter wire or fewer coils = higher spring rate. The static compressed load of the spring inside the booster is the critical detail, so you'll need to do some measuring and a little engineering.

Or you could go the other way- use the spring you've got and work up your loads until you find the max that setup will handle. Watch for smileys or rings around the case heads and of course any other pressure signs too. Extractor marks (bent or torn rims especially) are another sign of early unlocking under high pressure, and ejection distance is a useful thing to watch as well.

How about this https://www.mcmaster.com/#9657k363/=wdcqxw ?
Though I’d preferably want a flat wire 17-4 ph spring for longevity.

[ECCO Machine]

ECCO, that is completely false about muzzle brakes. They absolutely do delay slide unlocking, and in fact a good brake is the only way to safely push that kind of power level out of a Glock. Watch some slo-mo video, you'll see the bullet leave the barrel and the gas acting on the brake before the slide moves.

It's the weight of the brake, not the braking action. Ergo the "exceptionally heavy" language in my post; if you put a featherweight little titanium or aluminum critter on the snout, you'd be measuring the difference in acceleration and velocity in microseconds.

Now you need to go watch a slow mo video of a short recoil pistol with a bare muzzle so that you can understand that the slide & barrel barely move before the bullet exits on any of them. That's the point of locked breech short recoil. Once the bullet exits, the force accelerating the slide drops to virtually zero; it is strictly momentum that carries the slide & barrel rearward. Hence a muzzle brake or compensator cannot alter the slide acceleration & velocity via braking action, the redirection of gasses. Only by adding mass to the recoiling assembly, thereby increasing inertia, which means the same force will accelerate the greater mass more slowly and to a lower velocity in the same timeframe.

Heavier recoil springs don't do a lot for delaying unlocking, but they do contribute a little bit in a striker fired pistol, and a heavier spring is highly recommended for hot Glock loads.
.

Yeah, they add a whole 3 or 4 pounds against 3,000-5,000 pounds of thrust for your typical service pistol rounds Again, virtually nothing. A few dozen PSI variation between rounds makes more difference. Heavier recoil springs have no discernible effect on the rearward acceleration of the slide; they help with deceleration to reduce frame battering, and also cause more rapid acceleration returning to battery, ergo more force to chamber the next round.

[Hannibalbarca]

ECCO, that is completely false about muzzle brakes. They absolutely do delay slide unlocking, and in fact a good brake is the only way to safely push that kind of power level out of a Glock. Watch some slo-mo video, you'll see the bullet leave the barrel and the gas acting on the brake before the slide moves.

It's the weight of the brake, not the braking action. Ergo the "exceptionally heavy" language in my post; if you put a featherweight little titanium or aluminum critter on the snout, you'd be measuring the difference in acceleration and velocity in microseconds.

Now you need to go watch a slow mo video of a short recoil pistol with a bare muzzle so that you can understand that the slide & barrel barely move before the bullet exits on any of them. That's the point of locked breech short recoil. Once the bullet exits, the force accelerating the slide drops to virtually zero; it is strictly momentum that carries the slide & barrel rearward. Hence a muzzle brake or compensator cannot alter the slide acceleration & velocity via braking action, the redirection of gasses. Only by adding mass to the recoiling assembly, thereby increasing inertia, which means the same force will accelerate the greater mass more slowly and to a lower velocity in the same timeframe.

Heavier recoil springs don't do a lot for delaying unlocking, but they do contribute a little bit in a striker fired pistol, and a heavier spring is highly recommended for hot Glock loads.
.

Yeah, they add a whole 3 or 4 pounds against 3,000-5,000 pounds of thrust for your typical service pistol rounds Again, virtually nothing. A few dozen PSI variation between rounds makes more difference. Heavier recoil springs have no discernible effect on the rearward acceleration of the slide; they help with deceleration to reduce frame battering, and also cause more rapid acceleration returning to battery, ergo more force to chamber the next round.

Would the spring I listed help to retain more acting mass on the barrel? I’m not really familiar with the spring specs of recoil boosters.

[yondering]

ECCO, that is completely false about muzzle brakes. They absolutely do delay slide unlocking, and in fact a good brake is the only way to safely push that kind of power level out of a Glock. Watch some slo-mo video, you'll see the bullet leave the barrel and the gas acting on the brake before the slide moves.

It's the weight of the brake, not the braking action. Ergo the "exceptionally heavy" language in my post; if you put a featherweight little titanium or aluminum critter on the snout, you'd be measuring the difference in acceleration and velocity in microseconds.

Now you need to go watch a slow mo video of a short recoil pistol with a bare muzzle so that you can understand that the slide & barrel barely move before the bullet exits on any of them. That's the point of locked breech short recoil. Once the bullet exits, the force accelerating the slide drops to virtually zero; it is strictly momentum that carries the slide & barrel rearward. Hence a muzzle brake or compensator cannot alter the slide acceleration & velocity via braking action, the redirection of gasses. Only by adding mass to the recoiling assembly, thereby increasing inertia, which means the same force will accelerate the greater mass more slowly and to a lower velocity in the same timeframe.

Heavier recoil springs don't do a lot for delaying unlocking, but they do contribute a little bit in a striker fired pistol, and a heavier spring is highly recommended for hot Glock loads.
.

Yeah, they add a whole 3 or 4 pounds against 3,000-5,000 pounds of thrust for your typical service pistol rounds Again, virtually nothing. A few dozen PSI variation between rounds makes more difference. Heavier recoil springs have no discernible effect on the rearward acceleration of the slide; they help with deceleration to reduce frame battering, and also cause more rapid acceleration returning to battery, ergo more force to chamber the next round.

You don't seem to understand how brakes work. The part you said in bold above is correct, and that's why gasses pushing the brake forward counteract some of that recoil force and slow down the slide before it retracts far enough to unlock the barrel.

The results speak for themselves, even if you don't believe what you're seeing in slo mo video. It is NOT the weight of the brake doing the work. If you experimented with making your own brakes as I have, you'd see that pretty quick, there can be huge differences in slide velocity and unlocking timing between different brake designs of similar weight. And yes, I've made tiny lightweight titanium and aluminum brakes, and also heavier steel brakes. The weight does very little, it's the baffles that matter. If your brake designs aren't very good, then of course they won't do much to delay unlocking. But a good brake design can delay it enough to prevent a normal load from cycling with standard springs.

Unlocking delay is the reason the 460 Rowland requires a brake in a Glock, it's not just for recoil control. The only other way to get that much delay is to add lots of slide mass, which is impractical.

[ECCO Machine]

Would the spring I listed help to retain more acting mass on the barrel? I’m not really familiar with the spring specs of recoil boosters.

Probably, but we would need to know the rate of the one that comes with the booster. The McMaster-Carr offering looks to have much heavier wire and definitely fewer coils, so I'm sure it's stouter, but we don't know by how much.

There is really no standard for booster springs, but most are more similar to the McMaster-Carr spring than the squishy looking thing AJ Guns uses. That is, ~3/32" wire and 3 to 3-1/2 working coils.

[Hannibalbarca]

I think I found a spring I can use and I already have one.
The strike industries ar10 17-4 ph stainless flat wire recoil spring.
I have an extra one, I’d need to cut a portion of it off.

[ECCO Machine]

I think I found a spring I can use and I already have one.
The strike industries ar10 17-4 ph stainless flat wire recoil spring.
I have an extra one, I’d need to cut a portion of it off.

AR recoil springs are gonna be on the squishy side for a recoil booster, but probably no more than the one in that AJ Guns thing. Do put a finished end where you cut (bend the coil down to meet the next and grind to make a flat surface. Just clipping them and leaving unfinished ends causes distortion and binding, as well as wear on any shaft or bore they ride on/in. The Booster and piston already being soft 304 stainless, you don't want that.

[Hannibalbarca]

I think I found a spring I can use and I already have one.
The strike industries ar10 17-4 ph stainless flat wire recoil spring.
I have an extra one, I’d need to cut a portion of it off.

AR recoil springs are gonna be on the squishy side for a recoil booster, but probably no more than the one in that AJ Guns thing. Do put a finished end where you cut (bend the coil down to meet the next and grind to make a flat surface. Just clipping them and leaving unfinished ends causes distortion and binding, as well as wear on any shaft or bore they ride on/in. The Booster and piston already being soft 304 stainless, you don't want that.

I compressed down 3 inches of this spring and there was a considerable amount of force pushing back against my fingers. Much more so than the aj guns spring which feels almost nothing to me when I compress it.

[Hannibalbarca]

I’ll also be adding a weight to the pistol. A 3.5 inch 1.25 OD 316 stainless piece if round bar to add weight to the pistol using a single scope ring. Question though, will this lower the lifespan of the frame?

[ECCO Machine]

I’ll also be adding a weight to the pistol. A 3.5 inch 1.25 OD 316 stainless piece if round bar to add weight to the pistol using a single scope ring. Question though, will this lower the lifespan of the frame?

What, under the barrel on the rail? Why? You're already gonna be 4 pounds with that suppressor; why do you want to add another 20 ounces? Thing's gonna be heavier than a scoped Desert Eagle.

[Hannibalbarca]

I’ll also be adding a weight to the pistol. A 3.5 inch 1.25 OD 316 stainless piece if round bar to add weight to the pistol using a single scope ring. Question though, will this lower the lifespan of the frame?

What, under the barrel on the rail? Why? You're already gonna be 4 pounds with that suppressor; why do you want to add another 20 ounces? Thing's gonna be heavier than a scoped Desert Eagle.

I’m used to shooting my 42 ounce cz75 and would like to have the same balance as that. With the suppressor my center of gravity with the Glock will be significantly further up than with the cz but with the weight I can alleviate that somewhat.
Also, the 45 super(loaded to 460 Rowland levels) just has a lot more recoil than 9mm, 45 +p already feels a snappy to me in a steel 1911. With the extra weight it will be more controllable and feel more like 9mm from my cz.
I also think that the extra added weight might increase the lifespan of the frame transferring some of the energy that’s soaked into the frame to the steel weight but the added weight on the frame might do the opposite as well.

[ECCO Machine]

I’m used to shooting my 42 ounce cz75 and would like to have the same balance as that. With the suppressor my center of gravity with the Glock will be significantly further up than with the cz but with the weight I can alleviate that somewhat.

If you're trying to balance out that heavy can, you need to add that weight to the rear.

Also, the 45 super(loaded to 460 Rowland levels) just has a lot more recoil than 9mm, 45 +p already feels a snappy to me in a steel 1911. With the extra weight it will be more controllable and feel more like 9mm from my cz.
I also think that the extra added weight might increase the lifespan of the frame transferring some of the energy that’s soaked into the frame to the steel weight but the added weight on the frame might do the opposite as well.

Don't know that I've ever heard .45 ACP recoil referred to as "snappy", but why don't you try it with the can before you go adding chunks of metal.

And yes, it will be more abusive to the frame. Adding mass increases inertia; less recoiling of the frame with the slide=higher velocity impact when the slide hits home. Taken to extremes, think of a pistol just laying on a table versus one clamped rigidly in a vise. The pistol with nothing holding it will likely fail to cycle for the same reason that "limp wristing" causes cycling problems; there's a finite amount of energy available, and too much of it is used moving the entire gun instead of compressing the recoil spring. With rigid mounting, it's the opposite. People have cracked rifle stocks by putting a rigid stop behind the buttstock for bench work.

[AceInTheX]

I wanted to use a suppressor but it seems that the booster is so good at disengaging the weight of the suppressor that it won’t do anything to slide unlocking time. I was thinking of not using a booster but then I would imagine it would just be semi auto.

Anyone else catch this? Did you mean "slide action/singleshot" i.e. "not self loading"?

[Hannibalbarca]

I wanted to use a suppressor but it seems that the booster is so good at disengaging the weight of the suppressor that it won’t do anything to slide unlocking time. I was thinking of not using a booster but then I would imagine it would just be semi auto.

Anyone else catch this? Did you mean "slide action/singleshot" i.e. "not self loading"?

Yes, I meant that if I did not use a booster it would become single shot since there wouldn't be enough energy to chamber the next round. I definitely don't think a 21 z
Oz suppressor will cycle of without a boosters
Apparently that is not the case using the booster like I thought it would be, even with just a hollow tube and booster with no back pressure and when it weighs so much, comparatively speaking.

As mentioned by others, I can use a much Stouter booster spring to have more acting mass to delay the side unlock. I have an ar10 17-7 stainless recoil spring and I think that will definitely work.
Resistant to corrosion
Very stout and i can get a lot of Coils In
And also heat resistant.

[yondering]

As mentioned by others, I can use a much Stouter booster spring to have more acting mass to delay the side unlock. I have an ar10 17-7 stainless recoil spring and I think that will definitely work.
Resistant to corrosion
Very stout and i can get a lot of Coils In
And also heat resistant.

I don't think an AR10 spring is going to be stiff enough, think heavier than that. Also for a stiffer spring, less coils provides a higher spring rate, not more. More coils = softer spring

If you insist on adding even more weight to the gun, add it to the slide, not the frame. Forget about trying to make it balance like your CZ, that goes out the window with almost 2 lb of suppressor attached to the muzzle. On the slide, at least extra weight has the benefit of delaying unlocking a bit. If you're really not happy with the recoil of the 460 though, why are you wanting to do this? I have to imagine it'll suck to shoot suppressed (lots of blowback w/ powder particles to the face), and most likely won't be hearing safe even wet.

[Elkins45]

If you buy a Glock 30 kit from Rowland himself he makes you buy a “Rowlanator” which is an extra heavy metal rear sight designed to add mass to the slide. If I were putting weight on the gun I would put it on the slide.

FWIW I tried to run 45 Super/Low end Rowland loads in a Glock 21 using a crappy muzzle brake I bought off eBay and a threaded 45 ACP barrel with 45 Super brass. I added the strongest recoil spring I could find. What I discovered is that before I even got near Rowland levels I started having failures to feed because the magazine couldn’t deliver the next round before the slide was already back in battery. I bought extra power magazine springs and even doubled them up to make an Uber strong reduced capacity mag.

I gave up after that, but have since picked up a true compensator for the barrel, so I may try again. Clearly someone makes it work but my muzzle brake did little to slow down the slide.

When you think about what the gas pressure is doing it makes sense— the gas is acting against the baffle surfaces and are pushing the barrel assembly forward. It’s the same dynamic that causes silencers to also act as recoil reducers.

[Hannibalbarca]

If you buy a Glock 30 kit from Rowland himself he makes you buy a “Rowlanator” which is an extra heavy metal rear sight designed to add mass to the slide. If I were putting weight on the gun I would put it on the slide.

FWIW I tried to run 45 Super/Low end Rowland loads in a Glock 21 using a crappy muzzle brake I bought off eBay and a threaded 45 ACP barrel with 45 Super brass. I added the strongest recoil spring I could find. What I discovered is that before I even got near Rowland levels I started having failures to feed because the magazine couldn’t deliver the next round before the slide was already back in battery. I bought extra power magazine springs and even doubled them up to make an Uber strong reduced capacity mag.

I gave up after that, but have since picked up a true compensator for the barrel, so I may try again. Clearly someone makes it work but my muzzle brake did little to slow down the slide.

When you think about what the gas pressure is doing it makes sense— the gas is acting against the baffle surfaces and are pushing the barrel assembly forward. It’s the same dynamic that causes silencers to also act as recoil reducers.

Do you know how much it weighs?
Also if the spring is able to act enough on the barrel I shouldn’t have too much extra slide velocity. I think i will be going with the ar10 spring idea and work up the loads.