I would like to hear from anyone who has had a large rifle (.416 or up) that was not Mag-na-ported, but you later had the work done. You can make an honest comparison.

Here is my concern. My .458 Lott is handleable, but delivers about all the recoil that I can handle. However, muzzle flip is very substantial. I realize Mag-na-porting will tame the muzzle, but I understand that once ported much of the energy that went into the muzzle flip will now be directed back to the butt.

I have not had the change to test the before and after. What has been you experience?

Steve

Holtz, magnaporting will not increase the amount of felt recoil to the shooter. Because some of the propellant gases are directed upward so there is less gas pressure to push the rifle straight back at the shooter. In fact you should experience a small reduction in felt recoil(perhaps 3% to 4%). You are correct, manaporting will help tame muzzle jump.

Magnaport takes the upward jump out of a gun and that has to go somewhere and that direction is stright back..OUCH!

A KDF, Vias,Brockmon, and a slew of others will pull the rifle forward and they work much better than magnaport..I have used them all and if the magnaport was any good I would sure use it because it is nicer looking, but thats not the case at all...

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

I could tell no difference in recoil from my brother's 300 WM with/without the porting.

It did cause heavy copper fouling, the streaks started right at the ports. He sent it back to see if it had burrs or something. They returned it saying effectively "not our problem." The rifle had never fouled before.

He wound up selling it to somebody that wanted the action.

Don

I have two rifles that are Mag-Na-Ported, and I have chrono reports from before and after. If your rifle has a lot of muzzle jump, the Mag-Na-Porting will almost totally eliminate it. It does not have much affect on straight back recoil and I cannot tell much difference in shoulder felt recoil from either the M77 .458 Win or the 1895SS .45-70. But, rifles that use to jump several inches off the rest when shooting from the bench unless I held them down, now stay on the rest, not rising up at all even with the hottest loads. Velocity was not affected at all, before and after loads from the same lot of ammunition had the same average velocity well within the ES of the ammo. There is absolutly no truth that the energy is redirected backwards, and that would even violate laws of physics. Anyone telling you otherwise is having their perception of events clouded my misinformation, and then "feeling" the results that they think they should be feeling. Straight back recoil is controled by two affects, acceleration effects within the barrel which no porting or brake has much affect on, and gas jet effects, which is where porting and braking have their influence. Since braking redirects much more of the straight back jet affect they reduce straight back recoil more, which makes perfect sense. The porting only redirects a relatively small amount of gas up and to the side, which keeps the barrel from rising up, but does not reduce the jet affect much. However, the jet affect is reduced some, but straight back recoil from the jet affect is not reduced enough to be noticed in most cases, but the jet affect is certainly not increased as there is less gas leaving the muzzle after porting than before. People may argue otherwise, but physics doesn't lie.

Neither of my rifles had any increase of fouling after porting nor was there an increase or decrease in accuracy.

I'll have to disagree with Mr. Big Bore on this issue...For every action there is a reaction....muzzle brakes do one thing only and that is redirect gases..It the vents are angled forward they will push the gun back and visa versa..That is the principle of the muzzle break..The magnaport is directed upwards to push the gun down and rearward so as to get a quick 2nd shot, according to mag na port....

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Sorry, Ray, Big Bore's physics are right. Recoil is produced by imparting momentum to the bullet and the propellant gases. Maximum recoil occurs when everything goes out the front. There is NO WAY recoil can increase (or do anything but decrease, for that matter), if any of the gas is redirected or bled off. You've got less stuff going out the front; recoil goes down, even if only a little. For every action there is a reaction, and for every action that's slightly reduced, the reaction is slightly reduced.

Now, as BB said, you may have some preconceived notion of what it should feel like, so your perception is biased, but perception isn't fact.

As for Magnaport saying they redirect gas forward, that's the first I've heard of that (it's hard to "redirect" something to the same direction it was going in the first place).

Holtz, as to your original question, some of the energy that went into muzzle flip will be counteracted by the upward-directed jet of gas from the ports, but as has already been said, it will do very little for rearward thrust - the reduction will be only that amount of recoil that would have been generated by the gases that went up, instead of forward.

I have to agree with BB & FB, if there is less propellant gases coming out of the front of the barrel because propellant gas is being bled off by the magnaporting to force the barrel downward. Then there is less gas pressure available to drive the rifle back at the shooter. There fore the recoil should be slightly less, However the difference in felt recoil will be very small and more than likely will not be noticed by the shooter.

I know we are talking about magnaporting on rifles but. I own two 454 Casulls one has magnaporting and one does not. The gun that is magnaported does not have as much muzzle jump and has a bit less recoil than the unported gun. I think you will get the same result if you compare two identical rifles, that are ported and unported.

[This message has been edited by Mitch (edited 05-14-2001).]

Ray how about Brockmans Keeper porting system? He seemed to indicate a substantial reduction in recoil. What has been your experience? Thanks "D"

I am basically with Ray on this and I think some physics supports it.

Firstly, without any porting.

Let us say the rifle can be accelerated to 15 ft/sec by the recoil forces.

If the rifle rises during recoil the rifle has a momentum factor inthat direction, which means the monetum fact in rearward movement must be reduced.

Take an extreme to illustrate. Imagine you mounted a board on the butt that projected down 2 feet or so and you fired the rifle with the bottom of the board against your shoulder. You feel very little recoil.

I think we are dealing with (as near as I can remember) vectors.

Over the years I have had many switch barrel bench rifles in 270, 7mm Rem and 300 Win. If you put a heavy varmint taper barrel on, you become very aware that te rifle is moving back harder than when a lighter barrel is on the rifle.

A friend of mine has several rifles magna ported.

To me it seems to reduce "apparent" recoil for a couple of a shots. As such it seems like it is good for hunting game in conditions where very few shots are fired.

A few years ago we both had identical 358 STAs with his magna ported. I shot both rifles extensively of the bench, and I would agree with Ray.

By the way, these rifles are whaty we call "double magna ported". That is they have two extra lots behind the standard magna porting.

I think Rays posting applies more to the bigger bores than the small bore magnums.

I base this on my friends 7mm STW and 300 Wby and his new 300 Ultra.

In other words the reduced recoil on these calibers (where powder forms a larger proportion of the rcoil factor) is more thna enough to offset the more straight back motion.

Obviously with a handle like Mike375, I have seen and used magna porting on a 375.

I think it might have value for hunting where only a shot or two is fired. But for a lot more shooting, to me a 375 belts harder when magna ported.

Mike

OK guys if I make a recoil reducer and I angle the back holes to the front and the forward holes to the rear (to stop the blast) then why does it work less efficiently than if I angle all holes to the rear, BECAUSE it pulls the gun away from the body in simple terms it jets it forward..and you get more blast..I don't know where your theory is comming from but mine came from the makers when I started making them and I excepted it without question because it worked..
In test with the guns suspended on a pendleum in the American Rifleman the magnaport jetted rearward in a near stright line moreso than the others..The KDF won hands down, but that was before most were on the market...I also believe the larger the muzzle brake the better it works and thoes with interior chambers work better than thoes without....It is not a complex scenario, it simple re-direction of gas and you can make do anything you want...

Damn FB you done gone and done it, ya numbed up on me again!! (grin)

DeerHunter, yes the brockmon reducer works as well as any of them.

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Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Gentlemen:
I won't argue who is right or wrong on this one. I do know, that mag-na-porting does keep the muzzle down. This helps on a DGR rifle when you need a fast second shot. I have had several 416s without anything on the muzzle, and when shooting off the bench you will have to hold the fore end with a pretty good grip or it will leave the bags and fall to the right off the bench (for right handed shooters.) With the porting I do not even touch the fore end and it will go straight up and back down on the sand bag.
As to recoil reduction, I cannot tell much at the shoulder. Some years ago an article about mag-na-porting reported a 17% reduction with same. I do not remember the calibers. I will continue to use porting on all of my larger calibers, just because I like it. Grin.
George

I would have to agree with George Hoffman's general comments on this one. I purchased a .416 rem. in Mod. 70 a few years back and shot it quite a bit before I had it mag-na-ported. I believe at the time they said that Mag-na-porting would decrease muzzle jump substantially, and decrease felt recoil by something like 15%. I can attest to the muzzle jump claim,(George is right on with his description of shooting from the bench) but can't truthfully say that I noticed any difference in felt recoil.
For what its worth - Juneau.

Let me add my $.02 worth to this. When you shoot a rifle off a rest and the muzzle jumps up the energy used in making the muzzle rise
must be subtracted from the total recoil energy...muzzle flip + backward recoil = total recoil energy. Does it stand to reason that diverting some gas upward to reduce muzzle flip (work is not now being done by the rifle in flipping up) might make the rifle "feel" like there is more recoil straight back. I suspect the actual backward recoil is a bit less but it probably feels the same. It might help to think of the butt as a pivot point...as the muzzle rises without Magna-porting the whole rifle will pivot around the butt however if the muzzle doesn't rise there is not pivot. By the way, Ray is 100% right with respect to the size of brakes...the bigger the expansion chamber the longer the gas stays in the system and the better it works....this is one of the things that make the Vais brake so good. It actually slows the gas by changing direction and it is the velocity of the gas as it escapes that makes brakes louder.

I want to thank everyone for their input and good information. I have read all comments and am still hashing it over.

Steve

Hey Steve,

I have a Ruger #1H in .375 that I had Magna-ported. Before porting it was not very pleasent of the bench, just too much muzzle climb. I was always looking out for that nasty scoped "eyebrow", After the porting I can almost watch my bullet strike the berm @ 100yds. I think felt recoil seems about the same, but it is definetly more comfortable to shoot now, & isn't nearly as loud as a true muzzle brake. The only reason I don't have my Lott done is it has a NECG banded front & Magana-port won't guarantee it won't damage the front sight. I do think I get a bit nore fouling up front due to the ports, but, in a big bore you don't shoot a bunch, this isn't really a problem. Just my 5c's worth.

Last week I was shooting with a friend who has just pulled out his 505 Gibbs again. It is magna ported from the mfg 'smith (Somebody in Arizona). The recoil is not any greater and the rise is most definately reduced. It half turns him around with each shot but he says it's just fine. I looked at fouling after this thread started and there is none around the ports.FWIW

As a mechanical engineer reading these posts a smile came across my face, because just about everyone is correct in part. Rather than go through the physics and a discussion of momentum and accelleration (energy), I will just say that the physics are not necessarily determinative. Both momentum and energy of the gun in recoil will be less with Magnaport, but that does not mean that "felt recoil" will be any more or less with Magnaport. Shooting position, stock design, how you hold the rifle, your physical build and what you are used to will all play a role. Even muzzle jump itself may reduce felt recoil because the impact of the stock on your shoulder will not all be concentrated in one place, but will be spread out on your shoulder as the muzzle rises. It is too complex an problem to be worked out using simple physics. Until momentum and energy of the gun in recoil is reduced significantly it may not be the dominant factor in felt recoil.

Rob,

I didn't know you were a nuts and bolts geek like me, before you went over to the dark side and took up my wifes same chosen profession.

To the post at hand, there's lots of ways to deal with recoil, and every choice comes with a compromise, or a $ sign.

Personally, I think if more folks went to the cost of having someone who knows how to make a stock, make them a good one, then there wouldn't be nearly the market for these confounded gas blasters. Trouble is, a good stock is the most exspensive method of dealing with recoil, then again, it has advantages other then just helping one deal with the rearword and upward movement of their gun.

The 458 lott I had didn't have a magna port, but did have 10 1/4" holes drilled in a pattern of 4 at 1:30, 4:30, 7:30 and 10:30, 2 at 3:00 and 9:00, and 4 more at 1:30, 4:30, 7:30 and 10:30. The barrel was also backbored .470" dia for 1 1/2". Despite the symetrical porting, the gun exhibited very little muzzle jump, in fact offhand it seemed to just come straight back. I'm curious to shoot it now, as my buddy who bought it had it re-stocked.

As far as the rifle at hand, burning or boring holes in a barrel band front sight base has to be some sort of sin against fine rifledom. Brakes are bad enough, but butchering a barrelband sends shivers down me spine, I've seen it done, and the results are hideous.

Paul, I just don't admit to what I do for a living now, heh, heh.