Porting a 9mm Beretta?

[tobnpr]

My son's getting into 3-gun, and asked me to port his 9mm Beretta to reduce muzzle rise.
I'm a riflesmith...and I'm sure I "could" do it if I had a clue as to sizing/location of the porting in the slide and barrel...and then there's the burrs that would no doubt result and need to be removed...

For you pistolsmiths, is this straightforward enough- or should I just box it up and mail it to Magnaport and let them EDM it?

[JeepHammer]

Slots, 'D's, round holes?

Have you heard of Emery string? (Abrasive string?)

[T. O'Heir]

Porting the slide and barrel is done with an ECM/EDM machine, not a drill. And it has to be the right size and angle port too.
"...should I just box it up and..." Nope. Your son should.
Mag-Na-Porting is cheaper than installing a compensator. Those run about $300. Still his choice.
http://www.hec-computers.com/beretta...mpensator.html

[4V50 Gary]

American gunsmith had an article on how do to it with a drill.

I wouldn't do it that way though. I'd do it on a milling machine with an index head.

[tobnpr]

Slots, 'D's, round holes?

Have you heard of Emery string? (Abrasive string?)

I'm making no judgment on the type of porting...that's why I'm asking...
Objective is reduced muzzle rise for competition.
I'm trying to obtain information for the most effective shape, dimensioning and locations.

Sanding cord? Sure. Assuming you mean to deburr the holes; 'spose so but using abrasives in a bore scares the bejezus out of me.

" Nope. Your son should.

Nah...I'm a better father than that. He'd have to ship via FedEx Overnight. I can ship USPS...
Comp will add weight, which he wants to avoid.

Think I'll grab some rifle barrel take-offs/cutoffs and play around a bit to see.
But I'm thinking for $150 to have Magnaport do it.

That way he can't blame D.O.D. for his results lol (I'm much better at 1k yards, but he kicks my butt at ten).

[Scorch]

Recoil reduction (and barrel rise reduction) is done by changing the direction of travel of the high-pressure gases. Magna-Porting, while very clean and well marketed, does not significantly reduce recoil because it does not drastically change the direction of the gases (Magna-Porting ports are axial, the best ports are radial). You can do it with drills, you can slot it (radial, not axial), you can thread the barrel and put a brake on it.

[tobnpr]

Testing using a Ransom Rest on a Glock 19c shows a 30% reduction in muzzle rise, 24% after adjustment for velocity loss:


https://gundigest.com/article/ported...-reduce-recoil


Everything I've read online confirms the Autoporting reduces muzzle rise significantly, which is the objective here.

[JERRYS.]

EDM from MagNa-Port, inexpensive and done right with relative quickness.

[JeepHammer]

A bunch of muzzle brakes & porting are just plain done wrong.
Gasses angled the wrong direction, often directing overpressure back at shooter.
I do EDM most of the time, good clean removal with zero cleanup.

It doesn't really matter what shape the ports are, 'D' shaped ports simply release more gas, but I'm not fond of tight corners, going with ovals more than 'D's.
Tight, angled corners always make me think about cracks.

EDM takes equipment, it's not something the average gunsmith has laying around.
If you aren't already set up, this is an out of shop job.
As cheap as Magna-Port does it, I can't have the rods made for the price they charge.
Custom rods, minimum purchase, takes quite a while to make your money back...

[Jim Watson]

CAUTION: If Junior plans to shoot in sanctioned matches of USPSA Multigun or Three Gun Nation, he should be aware that barrel porting will put him in the Open and Unlimited divisions, respectively; closing off the less gear intensive divisons.

I don't think that muzzle rise is very bad in a big 9mm like that, I don't feel the need on my Colt or Smith, he might do better to put the money into practice ammo.

But if he just must, I would send it to Magnaport for superfluous holes. Machining is at risk of throwing up burrs in the rifling.
The charge for Autoporting through the barrel and slide is $145 but the open slide of the Beretta might let him get out for the same $99.50 as a revolver.

[JeepHammer]

'Burrs' or not, ... Depends on the guy running the machine...

'Burr', by definition, is a hanging piece of base material.
Very light lapping will remove anything hanging in the barrel, even rough leather will take of 'Burrs'.

Pressure Ridges are a different story...
With common (and current, that's why they are 'Common') pressure ridges stand up in about all barrel rifling, the reason for lapping rifling is so common.

Round holes, VERY sharp drill, very low pressure, lots of lube, small, and I mean SMALL pilot hole, very slow progression up to finished size will produce holes that have about zero burrs or pressure ridges.
You cutting metal instead of 'Punching' or 'Pushing' metal into the bore.
It's not hard to do, just a little time consuming...

With a oval slot, I suggest setting your slot stop ends with a head mill, then drilling out the excess material with a drill SMALLER than the width of the slot.
This is to allow a stright, side cut mill tool to cut slot sides instead of the drill.

Again, SHARP tool, lots of cooling/lube, move SLOW so the tool does the CUTTING instead of smearing metal.
Again, leather patch lapping will QUICKLY remove anything you can't deburr from the top.

Emery tape, strung between the opening of a 'C' shaped handle (like a coping saw holds it's blade, or dental floss/picks hold the floss) will allow you to hone away anything that is protruding into the barrel.
Keep it mind, even in a 9mm bore, this only takes 3-5 strokes, you are only double checking to make sure nothing is sticking into the bore.
Work at an angle to increase stroke and keep tape from cutting in, making serrations (like honing a long knife on narrow stone).

*IF* you pay attention to rifling rotation, this method will allow you to break over the shaving edge in your slot. MUCH less copper/lead will show up stuck in the port when you break that shaving edge.

Keep in mind the port does you very little good right out at the muzzle.
We aren't talking the length of the BULLET, but the bearing surface of the bullet.
The part of a fired bullet that shows rifling is the (Load) bearing surface.

Your ports should ideally start right behind the bearing surface length, from muzzle backwards the barrel. One bearing surface length behind the muzzle should be as close to the muzzle as you get.

----

I read somewhere that BARREL ports (not muzzle break ports that don't contact the bullet) should be kept in width to 1/8 the CIRCUMFERENCE of the bullet.
It was in a manufacturers tech drivel dissertation to the military, I have no idea if this is correct or not, and no way to test the information. Just passing it along.

[JeepHammer]

And, before the 'Haven't Done It' bunch blows the thread up,
Since you are lapping a VERY short area on one side of the barrel, right behind the muzzle,
Do the lapping the same way gunsmiths did with screw in front sight, where the drill/threading went into the bore for the last 200 years...

Simply use a hard wood dowel rod undersized for the bore, sand a spot down on ONE SIDE, use lapping compound on that sanded spot, use the far side of the crown for leverage.
Wood won't damage the crown in even the slightest.

On larger bores, you can angle sand, then attach leather to the end of the dowel rod in the width you want to deburr or lap.
The length of the lap depends entirely on the length of your stroke, the width of the lap depends on the width of your lapping tool and how well you control the lapping tool.

I go slow, use fine lapping compound so even if I do slip, it makes zero difference.

The lapped area will tell you where the high & low spots are with just hardwood & lapping compound.
Work the high spots! Most try to work the entire area, and you will spend the rest of your life trying to chase out low spots since lapping will show you every single imperfection in detail...
Work YOUR edges, and nothing else or you will loose your mind!

Keep in mind, you can cut your dowel rod to follow INSIDE the rifling grooves, not that you have to, the grooves are the least concern...
Ridges (Lands) are not even that big of a concern since it won't take long for bullets to remove any protruding material.
Keep in mind, it's at the edge of a hole, metal is easy to move when it's unsupported on one side...

[tobnpr]

Jim;
Thank you for the heads-up. I'll make sure he's aware of this...
He's getting to know his PX4 Storm, he's told me the high grip placement noticeably mitigates muzzle flip, but I haven't handled it yet. Come to think of it...seein' as he dropped it off to me last weekend I think I'll have to put a few rounds through it

JeepHammer;

Appreciate the detailed response- just what I was hoping for. Obviously need some quality time with some scrap barrel in the mill vise before working on the real deal, I'll expand my skill set (hopefully) while I send his off to Mag-na-port, after he confirms it won't screw up the Division in which he wants to compete.

[JeepHammer]

If it were lapping in the middle of a rifle barrel, it would be different, right at the muzzle, bore big enough to work in (even though it's REALLY short strokes) it's doable...

Details make the project!
When I sit down at a 12,000 grit stone to finish trigger sear profiles, then lap on a leather pad to polish, people think I'm nuts, but it makes for a super smooth trigger pull.
When people have to use a magnifier to find parting lines, I always get a kick out of it.

They give me a ton of crap about owning a 19th century manual screw cutter (watchmakers finger lathe) but those old guns have odd screws they don't make today, some are even tapered!
Try and find one of those at Brownells!

For deburring the bottom of a hole, you CAN sharpen a dental plaque scraping tool. It won't last long but low cost, cheap enough to be disposable. Tandsteen tool I think they are called...
It won't cut away seriously deformed metal, but when sharpened it will remove burrs.

Ultra fine firearms were made long before CNC & EDM...
I have a collection of watchmakers manuals, many made before the turn of the century, showing how to make all these super fine cuts, how to deburr those cuts, how lap fit parts where parting lines are nearly invisible.

'Mass Produced' & 'Fine Firearm' are mutually exclusive, no matter what the sales propaganda tells you!
Its good to have the skills even if you don't use them most times in the world of 'Black Guns'...

[Jim Watson]

Sounds good, Jeep. How much would you charge for that little job?
I one read about porting a barrel for ISU Rapid Fire to control the vicious .22 Short. The smith filled the barrel with Cerrosafe to prevent burrs.
My shotgun barrel got ported with a ball-end mill, machinist said that would give a cleaner hole than a drill. No problem cleaning up the inside, no rifling, no bullseye.

[T. O'Heir]

He's not going to learn how to do stuff if you do it for him.
"...much better at 1k yards..." What if he makes you run that far? snicker.

[JeepHammer]

I'm fairly well covered up right now, spring is always bad for me.
Everyone sits on their thumbs all winter, when the weather breaks good they freak out and I'm supposed to be the one that hurries to get whatever done...

I spend all winter processing brass, making parts, etc just trying to stay busy!

As for cost, $100-$150 depending on how elaborate.