Free bore boost without suppresor

[Dolomite_Supafly]

When using a suppressor there is a boost in velocity. The boost is attributed to the bullet not having the drag of being pushed down a rifled bore while still having pressure pushing it along. Also, accuracy increases are attributed to this also.

I was thinking why could a barrel that had the same features as a barrel with a suppressor not be made? Basically, a partially rifled with the remainder being opened up enough to allow the bullet to benefit from the free bore boost like a suppressor.

I know they make “bloop tubes” but the bore on those is much larger than the bullet. If the diameter of the smooth portion of the barrel was only slightly larger than the bullet would this cause an increase also?

A barrel does not need to be fully rifled to be accurate so this seems like this might work.

What do you think?

Dolomite

 

[Scotts556]

Re: Free bore boost without suppresor

Tag. I think u may be on to something here.


Scott

 

[BOLTRIPPER]

Re: Free bore boost without suppresor

are you two goobers drinking from the same beer bottle ?

 

[Shady_Jay]

Re: Free bore boost without suppresor

baffle the bullet so it traps its own sound










like swallowing a fart

 

[Cegorach]

Re: Free bore boost without suppresor

I am no ballistic expert by any stretch of the imagination, but it seems to me like that could potentially destabilize the bullet as turbulent gasses push past it without the stabilizing effect of rifling. I would think with a suppressor the gasses can escape into the can instead of being turbulent in a confined area as they pass around the bullet. Who knows, you could very well be on to something though.

 

[teknikallysekure]

Re: Free bore boost without suppresor

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Captain Kick-Ass</div><div class="ubbcode-body">baffle the bullet so it traps its own sound










like swallowing a fart </div></div>

lol

 

[nicholst55]

Re: Free bore boost without suppresor

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Cegorach</div><div class="ubbcode-body">I am no ballistic expert by any stretch of the imagination, but it seems to me like that could potentially destabilize the bullet as turbulent gasses push past it without the stabilizing effect of rifling. I would think with a suppressor the gasses can escape into the can instead of being turbulent in a confined area as they pass around the bullet. Who knows, you could very well be on to something though. </div></div>

How about using a bore evacuator like on a tank gun? It sucks up the excess gases after the projectile passes the gas ports mid-bore, and releases them out the muzzle once the projo departs the muzzle and pressure drops.

 

[Cegorach]

Re: Free bore boost without suppresor

That’s an idea, but wouldn’t it be more volume for expanding gasses to fill, and thus less pressure and less velocity. Maybe the net gain from the “boost” would outweigh it though. Heck, I am not even sure if my argument is valid.

To me it seems like an awful lot of work for a little gain. I mean what exactly are we looking + about 50 fps? It seems to me like there is more opportunity to degrade accuracy by fiddling around with the barrel and installing a bore evacuator. Maybe it could have an application in bench rest situations where even the smallest advantage is a big deal. In a practical tactical application I am not sure how much realistic gain could be expected.

I am not trying to bash, I am just attempting to reason it out in my head.

 

[Hummer]

Re: Free bore boost without suppresor

I have seen very deep counterbores on rifle barrels that cut like .325 and get one with a pilot ground down to .299. I saw one that must have been five inches deep.

 

[Geno C.]

Re: Free bore boost without suppresor

The guy that makes the 300 varmiter does something like this and calls it a quiet crown I think.

 

[LS6TT]

Re: Free bore boost without suppresor

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Captain Kick-Ass</div><div class="ubbcode-body">baffle the bullet so it traps its own sound










like swallowing a fart </div></div>

HAHAHAHAHHAHAHAHA very nice CKA

 

[Wheres-Waldo]

Re: Free bore boost without suppresor

Dolamite..good thinking, but you have a few invalid points...

You said: When using a suppressor there is a boost in velocity. The boost is attributed to the bullet not having the drag of being pushed down a rifled bore while still having pressure pushing it along.

The velocity increase comes from the added length of the supressor...much like a longer barrel would yield higher velicities.

We can contrast this with what you said by taking any ole' rifle, lets say a standard Rem VS for example, with a 26" barrel....Mine was getting around 2670 FPS with its fav. load.

Take that same rifle, and add a supressor, and ofcourse, we get what we expect, an increase in velocity.

Now this is different than what you are talking about. What your suggesting is that this 26" barrel would be SLOWER than an....oh, lets say 18" identicle barrel with an 8" supressor, giving the rifle the same over-all length.

Now its true that the 18" barrel with supression is faster than the naked 18" barrel, but it would be slower than the 26" barrel.

So, true, added length will give higher velocities, but lands n' grooves give more velocity than supression.

If one went with just smooth bore, there is less drag, or resistance. Any hand-loader knows that for any given powder, the heavier the projectile, the lighter his max charge will be. This is because smokeless powder has a burn rate which is directly proportionate to pressure. This means the more resistance a bullet has..(heavier bullet/larger bearing surface/more resistance)...the higher the pressure any given powder charge will produce.

Now...your smooth bore offers LESS resistance to bullet travel than lands n' grooves....less resistance, less pressure, or a sudden loss of pressure build/sustainment would result in LOWER velocity.

Another factor we could take into acount is the possibiliy of gas seaping around the bullet in the groove marks on the bullet, left by the rifled barrel.

This "could" cause inconsistant/irregular gas venting at the crown, which would be detramental to accuracy.

BTW: I just pulled this out of my ass, but it makes sense to me...
I hope I understood your proposal correctly.

 

[Dolomite_Supafly]

Re: Free bore boost without suppresor

Makes sense, I never put that much thought into it. This might save me some money because generally when I get a crackpot idea I go have soomething made to try it.

Last idea I had was my 7.62x25 Tokarev bolt action loaded with 180 grain bullets. That one worked out though and turned out to be a very accurate and quiet gun. An added bonus is that I could shoot surplus if I wanted to. Through loads I worked up I got it to be as quiet as a 22 lr while still having 357 magnum energy levels.

Thanks
Dolomite