How Does A Ramped Barrel Work?

[4sfed]

The barrel ramp/throat is NOT an extension of the feedramp...nor is it a bullet guide. It's a clearance. The cartridge should glance off the feed ramp and slid across the top corner of the barrel ramp...thus placing downward force onto the barrel and maintaining its position in the frame bed until the cartridge breaks over and enters the chamber.

Okay, I think I understand how Browning's design works . . . but what keeps a ramped barrel, like a Champion or Para, in position until the round breaks over?

[1911Tuner]

but what keeps a ramped barrel, like a Champion or Para, in position until the round breaks over?

Good question. It's a matter of the correct angle, mostly. Integral ramps don't leave a lotta wiggle room on that angle. It's either right...or it's wrong.

[niemi24s]

+1 on that being a good question.

My guess as to why a ramped barrel doesn't move forward & up is it gets hit at the same level as the frame would normally get hit by the bullet and the bullet is essentially moving straight ahead, with little or no upward motion. Bullet impact forces the barrel forward but also downward, due to the ramp's angle.

Although the bullet's point of impact on the ramp is still above the level of the slide stop pin (tending to lift the barrel through link action), maybe the downward nudge on the ramp cancels it out.

Or, maybe the extra weight of the integral ramp is just enough to keep the barrel from rising (?).

Or, maybe it's just magic! :D

[1911Tuner]

niemi...That's about as close as I can call it...but that's only half the problem that often rears up with a ramped barrel. The other part is in getting the round to break over to horizontal and enter the chamber. I've found that's usually the bigger problem, and the cure is most often to cut a small secondary angle at the top corner of the ramp. Seems like George Smith refers to it as a "Booster" angle. Basically, it entails cutting the ramp deeper into the chamber, which costs a little head support...but the remped barrels have an ample enough measure of that...so they can afford to lose a little. None have turned out to be excessive in any case. Plus, the secondary angle tends to give the bullet nose and the side of the case a better shot at holding the barrel down.

The location of the secondary angle is fairly simple. Color it with a sharpie marker and note the lowest spot that the bullet nose hits...and that's where it ends. Sometimes it has to be a tick higher or lower...depending on the gun and the original angle. Asking me what the exact angle is would be like asking your grandmother for her recipe for that killer pound cake. "I just add stuff 'til it tastes right." :D

George probably has it nailed down to an exact dimension.

[niemi24s]

Thanx 1911Tuner. With no experience with ramped barrels your info helps clear the fog.

Often makes me wonder how S&W got their now-discontinued Model 52 to swallow 38 Special WC's - the kind with NO nose (to speak of). A friend had one years ago and he said it never, ever failed to feed or fully chamber a round.

Sure is fun to wonder about stuff, huh? Cheers

[1911Tuner]

Often makes me wonder how S&W got their now-discontinued Model 52 to swallow 38 Special WC's - the kind with NO nose (to speak of). A friend had one years ago and he said it never, ever failed to feed or fully chamber a round.

Neat little pistol. I had one many years ago. It was designed to function with one specific round...that being the mid-range .38 Special wadcutter. Bump the powder charge up about 10-12% and they'd choke like a frog swallowin' a duck.

[4sfed]

niemi...That's about as close as I can call it...but that's only half the problem that often rears up with a ramped barrel. The other part is in getting the round to break over to horizontal and enter the chamber. I've found that's usually the bigger problem, and the cure is most often to cut a small secondary angle at the top corner of the ramp. Seems like George Smith refers to it as a "Booster" angle. Basically, it entails cutting the ramp deeper into the chamber, which costs a little head support...but the ramped barrels have an ample enough measure of that...so they can afford to lose a little. None have turned out to be excessive in any case. Plus, the secondary angle tends to give the bullet nose and the side of the case a better shot at holding the barrel down.

Tuner . . . my Para P14.45 had that problem with 200 gr SWC's. I modified the magazines to release the round earlier and more progressively. The change also allowed hardball, RNFP and Remington Golden Sabre's to chamber more easily.

Jim

[1911Tuner]

Yep. Magazines have a lot to do with it, too. It's a system. One area goes down...the whole system fails.

Congrats on the fix, by the way. Always satisfyin' to bring'em home alive. :cool:

[George Smith]

It is some magic.

couple things.
if the barrel foot hits the lugs on the barrel the barrel works better.
If you have a comp gun and the barrel link hits the slide stop and not the lug the link has more leverage and the bullet pushing forward on the barrel can wedge the barrel up inside the slide. Once upon a time a well known Smith published barrel fitting instructions that said to clear the bottom foot so the link touched when the barrel was locked down. It did NOT work causing a stoppage. It was exaserbated by comp guns.

on any gun but a para (para delivers the round higher than the others)
in a 45 the first round off the mag can dive down to .4 below the frame deck.
A ramp barrel is .3 from the top down, thus the "booster ramp is necessary to get the bullet fed up to the ramp barrel. Again in 45, 38 supers etc only need .280 from the deck down so the .3 deep ramp works well.

As tuner mentiones the booster ramp means moving the barrel ramp forward reducing support, not an issue with the low pressure 45.

On a Super the ramp me thinks wants to be around 26 degrees, Wilson managed to get guns to feed with 24 1/2 degrees and they worked, but I have no idea why :) . Impressive.
A std. 1911 45 frame is 31 1/2 degrees but on many current guns you can not get three and maintain a barrel gap at the top of the frame.

I do not have a solid number for the angle that the 45 stops working on, I suspect 28 degree ramps will work. test firing and dry feeding is the key.
and the issue is invariably the first round from a full mag. 3 rounds in a 45 mag don't go down the feed ramp anywhere near as much as the top round.

Also this is the reason for the futility of using a ramp barrel in a 45 to cure the issues with an aluminum frame. It don't work long :)

best regards
geo

[1911Tuner]

Ahhhh...Thanks, George. The only problem is that...if you don't an exact angle nailed down...nobody does. ;)

Fellas...I might have mentioned that I owe George a huge debt of gratitude. For 13 bucks, he's made available his square-bottomed firing pin stops...and I don't hafta make'em any more. :D

[4sfed]

It is some magic.
<snip>
A std. 1911 45 frame is 31 1/2 degrees but on many current guns you can not get three and maintain a barrel gap at the top of the frame.
best regards
geo

George,

Can you clarify this? I'm afraid you lost me . . . "can not get three" what?

Thanks,

[auto45]

So.... what's the point of a ramped barrel in 45 ACP? :)

I have yet to hear a "positive", and yet, several manufacturers use them!

And, do you need a ramped barrel in other calibers if you stay within their "intended" power perimeters...9mm, 40 ,etc?

[1911Tuner]

So.... what's the point of a ramped barrel in 45 ACP?

I have yet to hear a "positive", and yet, several manufacturers use them!

Well...ummmm...Well...I really can't think of any, except that it offers full head support for those who wanna try their luck with the hot-rod wildcats like the .45 Super or the like. Why do several manufacturers use'em? Maybe because it's the current trend?

It all really got started several years ago when the shooters discovered that they could push the envelope with the .38 Super with 150-grain bullets and make major...along with doublestack guns in that caliber. I seem to remember that the guys also used small rifle primers because the cups were thicker and resisted blowouts better than pistol primers...Good idea when you're essentially using near proof loads with heavier than standard bullets.

[twin oaks]

One thing about the ramped barrel is that the gap at the top is constant. There is no movement between the barrel ramp and the frame ramp, as it's one piece. Therefore, you reduce or eliminate a bullet nose striking the barrel ramp, shoving it forward, and causing a 3-point jam. IF the angle is right, a bullet that struck the ramp will be deflected upwards, and any movement should already have happened when the meplat reaches the 'barrel ramp' portion of the breach.

[1911Tuner]

One thing about the ramped barrel is that the gap at the top is constant. There is no movement between the barrel ramp and the frame ramp, as it's one piece. Therefore, you reduce or eliminate a bullet nose striking the barrel ramp, shoving it forward, and causing a 3-point jam.

Nope. The barrel will still move forward if the angle isn't right...and in the standard configuration...if the feed ramp angle and barrel ramp geometry are right...the bullet nose won't hit the barrel anyway. The round glances up on the feed ramp and skids over the top corner of the barrel ramp.

The trick is to get the angle steep enough while still allowing the cartridge to get into the chamber and hold the barrel down without pushing it forward. Do that...and the gun will feed like green grease through a goose.