Inertia Recoil Reducer

gofishingup

I'm in the process of planning to have a single shot rifle built in a 300 PRC. I'm looking at putting a Terminator No. 2 or 3 muzzle brake on the rifle (which one I choose will depend on the diameter of the barrel as there is not much difference in reducing recoil between the two of them) but I don't know if there would be much benefit of also going with an inertial recoil reducer in the stock. I know some advertise a 20% reduction in recoil. Does anyone have an input on the issue? Is the added weight worth the trade-off?

Second issue, I'm considering fluting the barrel. I know some are against this. With this gun, it will be a hunting gun and will be shot less than 10 times per year so I'm not concerned about barrel life. I believe fluting the barrel removes about 6-8 ounces from the weight of the gun. Any thoughts on what this equates to in regard to added recoil? My thoughts on the issue, I want to keep weight down but want a gun that is decent on recoil. If I add the Terminator muzzle brake I can compensate for the added weight by fluting the barrel so I think it's an even trade off. What benefit if any is there to then adding an Inerta Recoil Reducer in the stock? I have "0" experience with them. Is there a benefit to balancing out the weight of the rifle? Again, this is a hunting rifle so I'm not concerned with long range target shooting but I want to be able to shoot out to 350 yards if need be.

I know the gun I want will be expensive to build so I want to do my homework before hand and not get the rifle made and then discover I should have done something different. Any input anyone has is appreciated. Also, does anyone have an experience with a good gun smith working with single shot rifles? There aren't a lot of them out there. I'm talking to two up in Canada who seem to be experts but I'm open to any suggestions if anyone has had any experience in this field. Thanks.

GunNut

Muzzle break will be your biggest bang for the money in recoil reduction.  When it comes to weight of the gun the equation is simple.  More weight, less recoil so taking it from one place and moving it to another won’t make a huge difference.  Stock geometry and a wide/soft recoil pad also make a big difference.

I prefer light hunting guns with no breaks even in bruisers like my 7lb .35 Whelen which WILL let you know you shot a rifle.   Like you said, the gun doesn’t get shot much, you really won’t notice recoil while hunting and on the bench I use a Past recoil shield.

Spk

GunNut already talked to the core of this issue. I'll just add a few small bits.

gofishingup said:

...

I don't know if there would be much benefit of also going with an inertial recoil reducer in the stock. I know some advertise a 20% reduction in recoil. Does anyone have an input on the issue? Is the added weight worth the trade-off?
...

If I add the Terminator muzzle brake I can compensate for the added weight by fluting the barrel so I think it's an even trade off. What benefit if any is there to then adding an Inerta Recoil Reducer in the stock? 
...
I know the gun I want will be expensive to build so I want to do my homework before hand...

Like GunNut said, a brake will be your best buddy. At 6.5 lbs, your rifle launching 225 grain bullets at about 2800 fps is already putting you in the 50 BMG category (assuming a 30 lbs rifle). The 300 Win Mag and a 9 lbs rifle puts you in the 27-30 ft-lbs of FRE territory. Your rifle puts you in the 45-50 ft-lbs range.

So first off get a good brake. Maybe even a Rifle Compression Butt Plate. As to the Inertial Recoil Reducer, at minimum it'll add weight. The goal isn't going to be recoil elimination but instead it'll be recoil management.

If you can spread the recoil out over a large enough timespan, it won't seem like a big deal. Take these graphs, for instance:

Compare the above with:

The more you can spread the Impulse out, the lower the peak force and the more mild it will feel. Even though, the total free recoil energy (fre) is still there. The amount of work hasn't changed (the area under the curve) but it will sure "feel" better on your shoulder!

Btw, some companies even claim as high as 40%-50% reduction. I don't know what they're measuring but at the minimum, your adding some weight to the rifle and that alone will help a bit. 😁

Jayhawker

Well...why not see what your muzzle brake does for you before you take it any further....My brake calmed my .300 W.M. down to .243 levels..
You may get what you need without ending up with an unnecessarily heavy rifle....
.

Gene L

So did mine on a .300 WM.  It was ugly and had to be sweated on, but boy did it knock the recoil down...I paid the price however in muzzle blast.  Uncomfortable. not  a strong enough adjective.  It was significant factor in shooting, the ear-blasting noise coming from both sides.

I won't do that again.

tennmike

High efficiency muzzle brake and a shotgun width recoil pad will be your best bets for recoil reduction. I have had some experience with the old mercury filled recoil reduction system, and I'll take a good brake every time over that; muzzle brakes WORK!

Linefinder

Muzzle brakes do work. I can launch 40 grain VMaxes from my braked .223's at 3800  fps and the rifles barely even shiver. That's important against pdogs so you can spot your misses exactly before the wind drifts your dust cloud a couple feet. Makes correcting much easier.

My braked 6mm Rem launches 75 grain VMaxes at 3750 with almost the same effect. Funny thing, though....95 grain NBTs at 3250 knock me out of the sight picture every time. I've never figured that out.

Mike

CHIRO1989

Linefinder said:

Muzzle brakes do work. I can launch 40 grain VMaxes from my braked .223's and the rifles barely even shiver. That's important against pdogs so you can spot your misses exactly before the wind drifts your dust cloud a couple feet. Makes correcting much easier.

My braked 6mm Rem launches 75 grain VMaxes at 3750 with almost the same effect. Funny thing, though....95 grain NBTs at 3250 knock me out of the sight picture every time. I've never figured that out.

Mike

Dude, you weigh like a buck twenty, recoil is overcoming your friction on the ground  

Spk

Linefinder said:

...

My braked 6mm Rem launches 75 grain VMaxes at 3750 with almost the same effect. Funny thing, though....95 grain NBTs at 3250 knock me out of the sight picture every time. I've never figured that out.

Mike

Just for starters your 95's carry more momentum.

(95×3250=308.750 PF versus 75×3750=281.250 PF)

I don't know what your load is but I'm guessing your PF is part of the issue.

At least you're not this guy.

Linefinder

Well, Spk, I don't know what a PF is, but that might explain why I didn't actually see what's likely the best big game shot I've ever made.

Some years back JerryBobCo and I were after pronghorn. He tagged out well before 9AM, scoring his largest racked buck to date. It was an impressive critter. I hadn't been in range of a shootable one all day.

Around 2PM I was about ready to call it a skunk when we saw a group of antelope on the adjoining (meaning non-huntable) property almost a mile away. It appeared to be 9 does and one buck, and even at that distance the buck looked like a really good one. We watched them for probably 45 minutes, just grazing, when they suddenly started moving in our direction. Jerry changed positions, allowing himself to be seen,  hoping to move them a little more in my direction.

Long story short, the herd came across the field diagonally, getting closer. I was in a sitting position, watching, when they suddenly broke into a full on blue-smoke run. Knowing this was likely going to be my only chance this season, I pulled down about 8 feet ahead of the buck and squeezed the trigger. Scope black-out, and it sounded like my bullet crashed into the trees 500 yards away.

Coming down off recoil, I jacked another round into the chamber and reacquired the herd just as it was crossing the fence back into no-man's land. But.......I didn't see a horn in the bunch.

A few minutes later Jerry pulled up in his truck and asked me why I hadn't shot. I told him I had, and why the heck wasn't he watching? He said that when he saw the antelope turn toward me he took cover behind his truck, because he'd been shot before and, no offense, but better safe than sorry....or something to that effect.

I mentioned I hadn't seen a buck among the group when they recrossed the fence, and he said he hadn't either. A short while later, we were taking pictures of a buck only 1/8" smaller than the trophy he'd shot that morning. 210 yard away on a dead run....

With two witnesses on hand.....nobody actually saw the best big game shot I've ever made.

I've gotta figure this PF stuff out.

Mike

Bigslug

It's very much a personal topic, so before sinking a lot of money into a build, you might want to track down and shoot some braked guns.

Personally, recoil - especially on a low round count hunting rifle - is far less of a problem for me than the concussion generated by a muzzle brake ( I HATE brakes) or carrying the weight of a heavy gun (Getting older, and going to the gym is something I face with the reluctance of being a rower on a Roman slave galley).

If you've got recoil sensitivity issues, you might also consider the mission and look at cartridge/projectile combinations that will do the same job without exceeding your comfort envelope.  For example, dropping down to 7mm (.280 Rem maybe) can flatten trajectories and selecting a sturdy bullet (Barnes TTSX) will provide plenty of penetration.

Rather than flute, I think a standard barrel of thinner diameter is the better way to go.  This is not a bench gun that has to deal with a lot of heat.  You can get PLENTY of accuracy out of a sporter weight barrel - especially if time is taken to cut, fit, and bed it carefully.

Spk

Linefinder said:

Well, Spk, I don't know what a PF is, but that might explain why I didn't actually see what's likely the best big game shot I've ever made.

.....nobody actually saw the best big game shot I've ever made.

I've gotta figure this PF stuff out.

Mike

I'm sorry to hear you didn't get to see the best shot of your life 😂

If you have some time to read. This is a good article on PF (Power Factor)

https://www.ssusa.org/articles/2016/1/27/understanding-the-power-factor/

It's just (Bullet Weight × Muzzle Velocity)÷1000

This gives you a number that's related to momentum. By Newton's Third Law, whatever you push in one direction pushes back equally hard in the opposite direction. I could show you the math but some members would be bored to tears. 😫😫😫

Anyway, the article is a fun read.

Next time do what Zee does. Bring a video camera and mount it somewhere.

Linefinder

Thanks for that. I'm going to read thar in a little bit.

I never figured out why a bullet only 20 grains heavier, but traveling 500 fps less, could produce such a marked difference in recoil.

Mike

earlyagain

Along time ago in a movie far away. A famous singer shot a turkey with a Sharps 50 carbine. A famous cowboy actor with an eye patch uttered a simple phrase when he saw the chewed up bird.

snake284

There's a lot of hooplah about the muzzle blast from a braked rifle. I don't have issues with it myself. I wear hearing protection regularly whether at the range or hunting. Actually I used to not wear it hunting because I couldn't hear animals approaching. Then I found my hearing aids blocked most of the excess decibles  of my rifles. If you don't wear hearing aids you might want to look into something like Walker's Game Ear. If I had to do it over I never would have exposed myself to gun fire without hearing protection. With my hearing aids in the brake doesn't other me. I don't notice it. And it knocks the recoil of my .300 WBY Mag down to something like a .308.

Spk

Linefinder said:

Thanks for that. I'm going to read thar in a little bit.

I never figured out why a bullet only 20 grains heavier, but traveling 500 fps less, could produce such a marked difference in recoil.

Mike

Another way to look at it is like this:

[email protected]

[email protected]

Therefore:

95÷75=1.266666666 or 1.27

This is about a 27% increase in mass (bullet weight) from 75 to 95.

Versus:

3250÷3750=0.86666666 or 0.87 or a reduction in speed of about 13%

So we increase the weight by about 27% and only decrease the speed by about 13% so my overall PF will increase.

I would need a proportional decrease in speed of about 21% to compensate for my roughly 27% increase in bullet weight. (21% reduction from 3750) About 2960 fps would do. (You'll notice it's about a 27% increase from 2960 to 3750)

Therefore, 95×2960=281200

Or 281.2 PF

The same as 75×3750=281250 or 281.25 PF

The whole divide by a thousand thing is just a matter of moving the decimal point over three spaces. I don't bother writing it out.

Once you have a handle on PF there's some other cool stuff you can do.

It's easy. 😏

ETA: Like I mentioned earlier, PF is only part of the picture. You have to look at the cartridge load as well.

Spk

knitepoet said:

I just use online recoil calculators to figure it out. A lot easier, IMO

https://www.jbmballistics.com/cgi-bin/jbmrecoil-5.1.cgi

http://www.shooterscalculator.com/recoil-calculator.php

Those calculators are fine if you want to figure out Recoil Energy, Recoil Velocity and Recoil Impulse but they don't do PF.

Luckily, JBM has a page for that also.

http://www.jbmballistics.com/cgi-bin/jbmpf-5.1.cgi

All you need for Power Factor is Bullet Weight and Velocity. The third one, (caliber) isn't involved in the calculation but it's sometimes used to determine what classification you'll be shooting in (Shooting Sports stuff)

I've seen this happen before, a new shooter will come in and say something like, "I wanna shoot Minor (PF 120 but below 165) and I want to used my 130 gr cast bullets. What velocity do I need to make Minor?"

Since the online calculator doesn't cover that, a basic understanding of what's happening can be useful. One approach is to guess at a velocity using the online calculator and eventually you'll get the right answer or could just solve it directly. I usually just go the direct approach.

Definition:

PF=Bullet Weight×Velocity

Known:

PF>120 and Bullet Weight=130

We're looking for Velocity....(hmm?)

Just rewrite the equation of

PF=Bullet Weight×Velocity solving for Velocity.

Velocity=(PF×1000)÷Bullet Weight

It would look like this:

(120×1000)÷130~923

Checking: 130×923~120,000

Move the decimal over and you get 120. So you need a velocity over 923 fps. I would shoot for 950 fps and call it good.
Simple things like this help you avoid headaches later.

Believe it or not, I use online calculators alot but when something looks funny, I know how to check my own work. It's useful. 👍

Spk

But then again, if I'm trying to figure out why something kicks the way it does I'll go straight to the calculators. I use PF as a quick check. Usually, if the PF says it's cool then I'm done fiddling around. Otherwise, I'm off to a calculator page or phone app. Sometimes I'll do it by hand just to understand the problem better.

But that's just me. 😉

Linefinder

I haven't done any of the math yet, but this is what I find curious.

75 grain VMaxes from my braked 6mm Rem 700 VLS (weighs a ton) at 3800 fps, I stay in the scope.

130 grain NBTs from my BOSSed 270 Browning A Bolt Hunter (pretty light) at 3020 fps, depending on body position I usually stay in the scope.

95 grain NBTs at 3250 from the same 6mm platform.....things go dark every time. 

While the felt recoil of any isn't bad, the 270 is by far the most noticable. But I can still see my hits (or misses). Except with the 6mm 95 grainers. Using those I usually have to do a ground search to verify the results.

Curious.

Mike

earlyagain

Stock shape and fit are a big contributor too.

My Stevens 311A knocks me hard well my much lighter Mossberg pump is a kinder, gentler 12ga kicker.

Zee

A well designed and well built muzzle brake is worth it’s weight in gold. 

Often, the less informed and less experienced consider muzzle brakes to only be used for recoil reduction. This, is a narrow minded fallacy. 

Their use and effectiveness transcends simple recoil (pain) reduction and aids in a plethora of shooting aspects. 

-Muzzle Rise Reduction
-Impact Identification 
-Alternate Position Shooting
-Position Maintenance (NPoA)
-Follow Through / Follow Up Shot
-Suppressor Attachment

I have brakes on the vast majority of my Rifles and Specialty Pistols. Many of which are typically low recoiling cartridges to begin with (.223 Rem / 6x45 AR / .243 Win / .260 Rem / 6.5-284 Win / etc)
The decision you do so has nothing to do with painful recoil and everything to do with reduction of muzzle rise. My goal is negating firearm movement. 

A good muzzle brake is an awesome thing. 

Skip the inertial reducer if weight is a issue. Pound for pound, a good brake is more effective (see what I did there). 

Spk

knitepoet said:

...

Since you seemed to be using PF to explain recoil, figured I'd throw some accuracy in the mix on the recoil.

I can assure you that, say, 10ft/lbs or recoil can feel quite a bit different from a super light rifle (moving faster) versus a heavier one. Higher recoil velocity makes for "sharper" recoil, while slower makes it feel more like a shove

I was just using it as a quick check since Mike didn't give his charge weight or rifle weight. He essentially gives two things in that first post, bullet weight and velocity. So I used PF to see what it say about the matter.

I'm well aware that having a light versus heavy rifle makes a difference. Recoil velocity plays a role or like Early points out stock geometry and other factors play a role. But until Mike tells these things, I'm just using PF as a quick check and since he mentioned and interest in learning more about it I thought I'd give him more info. I was not trying to explain Recoil through Power Factor but showing that it's associated with Recoil. I hope that sheds some accuracy in my bringing up PF in the first place.

Linefinder

I use H4350 for both bullets. 49 grain charge weight for the 75 VMaxes, and 46 for the 95 grain NBTs.

I've never weighed the rifle, but it's a 700 VLS with heavy varmint contour  and I'm guessing with laminated stock, scope, and bipod it's gotta be weighing in around close to 11.5 to 12 lbs. (It's not a fun mountain rifle though I've used it for that).

Checked my records for velocity. 75 grainers at 3750. 95s at 3250.

Mike

Linefinder

earlyagain said:

Stock shape and fit are a big contributor too.

My Stevens 311A knocks me hard well my much lighter Mossberg pump is a kinder, gentler 12ga kicker.

I had a '94 Win in .32 Spl and one of my friends had the same chambered in .30-30. Almost identical ballistics. But my .32 would knock the wet dog snot out of you, while his .30-30 was a puddy.

Never figured that one out either.

Mike

GunNut

Linefinder said:

earlyagain said:

Stock shape and fit are a big contributor too.

My Stevens 311A knocks me hard well my much lighter Mossberg pump is a kinder, gentler 12ga kicker.

I had a '94 Win in .32 Spl and one of my friends had the same chambered in .30-30. Almost identical ballistics. But my .32 would knock the wet dog snot out of you, while his .30-30 was a puddy.

Never figured that one out either.

Mike

Same weight bullets?  The 30-30 comes in 150 and 170 grains in commercial loads but the .32 is a 170 grain only proposition and for whatever reason I’ve always found the 150s to be easy on the shoulder, specially with the older steel butt guns and the 170s will let you KNOW you touched the trigger.  Just curious.

Linefinder

I don't recall my friends bullet weight (40+ years ago), but I feel sure it was whatever was the most commonly available at the time. They both had steel butt plates, I do remember that. 

While my .32 Spl was a beautiful 50's build, with the nicest bluing I've ever seen, I never enjoyed shooting it. 

Mike

earlyagain

More subjective perception. Maybe because of body type or shooting style? Win 94's in 30-30 always kicked me hard. Maybe it was the 170gr loads. Back then I didn't pay that much attention to bullet weight.

Spk

Linefinder said:

I use H4350 for both bullets. 49 grain charge weight for the 75 VMaxes, and 46 for the 95 grain NBTs.

I've never weighed the rifle, but it's a 700 VLS with heavy varmint contour  and I'm guessing with laminated stock, scope, and bipod it's gotta be weighing in around close to 11.5 to 12 lbs. (It's not a fun mountain rifle though I've used it for that).

Checked my records for velocity. 75 grainers at 3750. 95s at 3250.

Mike

Using the JBM recoil calculator Knite provided and the data above I get:

[email protected] 49.0gr and a your heavy ~ 11.5 lb rifle I get.

Recoil Velocity -- 6.4 fps

Recoil Impulse -- 2.3 lb•sec

Recoil Energy -- 7.2 ft•lbs

[email protected] 46.0gr and same 11.5 lb rifle gives:

Recoil Velocity -- 6.5 fps

Recoil Impulse -- 2.3 lb•sec

Recoil Energy -- 7.6 ft•lbs

These results confirm what the PF was telling us. That your 95's just kick a bit harder.

You can can run the results yourself here:

http://www.jbmballistics.com/cgi-bin/jbmrecoil-5.1.cgi

Using the 12 lb rifle just shifts all the values a bit lower across the board but the end result is the same. The 95's are a bit more rambunctious. 😁

Spk

Linefinder said:

earlyagain said:

Stock shape and fit are a big contributor too.

My Stevens 311A knocks me hard well my much lighter Mossberg pump is a kinder, gentler 12ga kicker.

I had a '94 Win in .32 Spl and one of my friends had the same chambered in .30-30. Almost identical ballistics. But my .32 would knock the wet dog snot out of you, while his .30-30 was a puddy.

Never figured that one out either.

Mike

This one has a few too many variables floating around. It could've been the loads you were using (factory?) If they were both factory then there's really no telling what was going on.

Linefinder

Yes, they were both factory loads, for sure. We were kids and didn't reload at the time.

But I have read on more than one site that the .32 Win Spl would knock you around a lot more than the .30-30.

That was certainly my experience. 

That rifle was stolen when I was 16. While I wish I still had it, I'm glad I haven't had to shoot it since then. LOL.

Mike

Spk

It was also marketed as something more powerful than the .30-30 and yet had less recoil than the .30 Army.

https://en.m.wikipedia.org/wiki/.32_Winchester_Special

More power by about 5%-10%

What I've noticed and you probably already know is the 30-30 comes with a wider selection of ammo choices in factory loadings than the 32. The 32 Spl had maybe 2 choices (170 and 165?)

Ballistically there's not much difference between the 170's in both calibers but things change a lot when you start comparing the lighter loads in 30-30 to either of the 32 offerings.

I ran a PF on one 30-30 load in the 110 grain offering and it gave me 298. I ran a 170 offering in 32 Spl and it rang the bell at 388 PF! The 165 offering was worse at 398! I ran some 30-30 loads in the 170 offering and they also hit the upper 300's.

I'm just wondering if it's possible you guys were shooting some of the lighter 30-30 loads (possible?) Maybe something like the 130's or 150's.

My friends dad growing up had a 30-30 on his ranch and I only remember him shooting the 130 grain loads. For some time, I thought the only load available was 130.  😁

Anyway, maybe whoever stole that rifle regretted it later. I sure hope so 😡.