Grendel and 5R Rifling (Haters gonna Hate)

[LRRPF52]

If you read through the thread, you'll see that another 5R rifled barrel was used as a comparison. Furthermore, all the barrels were in the mid-2600's for mv. What you will notice is that XCR's 24" barrel is generating erratic velocity with a significant Extreme Spread (ES).

24" Satern: 2638, 2637,2645,2635,2641
24" Liberty: 2660, 2675, 2681, 2648, 2701

That's a spread of 2648-2701fps, or 53fps. Notice that the Satern barrel had an ES of 10fps. They were shooting the same load from the same box. XCR's Liberty barrel most likely has a tight bore on it, which will build pressure faster. That said, the velocities are not significantly higher than other barrels of the same length, as demonstrated here.

[Tedward]

I do agree with you on that. What would cause the spike or drops to get the ES of 53? The ES of 10 seems better so you know what your going to get and might provide more accurate shooting. If you get the spike of +53, that might make your shot more inaccurate.

So if that's what your getting at, yes, not good I would say but just my opinion.

Is this what you and Drifter are getting at???

[XcountryRider]

I do agree with you on that. What would cause the spike or drops to get the ES of 53? The ES of 10 seems better so you know what your going to get and might provide more accurate shooting. If you get the spike of +53, that might make your shot more inaccurate.

So if that's what your getting at, yes, not good I would say but just my opinion.

Is this what you and Drifter are getting at???

The Saturn 5R Cut rifles are pretty darn awesome and the low ES also helps rickoshay with is tiny little pretty groups with over lapping holes!! Your not going to get that kind of precision with a Liberty 5R button rifles as stated by Saturn on there site. If you would why pay more for the cut rifling? Get the Liberty if you want a good 18in hunting stick where the extra velocity matters more than overlapping holes. If you want to post up tiny little groups on 65grendel get the Saturn 5R rifle cut. You'll pay more but if thats what you want then its probably worth the extra coin.

[Tedward]

The Saturn 5R Cut rifles are pretty darn awesome and the low ES also helps rickoshay with is tiny little pretty groups with over lapping holes!! Your not going to get that kind of precision with a Liberty 5R button rifles as stated by Saturn on there site. If you would why pay more for the cut rifling? Get the Liberty if you want a good 18in hunting stick where the extra velocity matters more than overlapping holes. If you want to post up tiny little groups on 65grendel get the Saturn 5R rifle cut. You'll pay more but if thats what you want then its probably worth the extra coin.

I got it now and I could probably buy the most expensive barrel and probably still not get the tiny pretty little holes. I'll try the Lilja but that will be my bench barrel (AR24) and my Stoners are for the woods.

Now it is all getting clearer and I'm understanding the difference in the group and speed variance. I hope this end here on this trend helps the ignorant guy's like me to understand more speed doesn't make it better or more accurate.

[rickOshay]

I guess the only issue left in this thread is whether all Liberty barrels produce slightly higher MVs. Until we have more data, I would be hesitant to say that they all do. I know XCR has measured three barrels, all likely from the same lot (purchased from Midway at the same time). More Liberty barrel owners, please step forward.

What we have learned is the higher velocities are not due to 5R rifling, and XCR's chrony is reading correctly. XCR has backed off from those extremely high re-loads and is aware of the signs of overpressure.

And we all agree that hunting accuracy is different from target accuracy. However, if your quest for higher velocities is to extend your hunting reach, then accuracy comes back into play. And that high ES will make it hard to know which speed to hold for when you pull the trigger.

[LRRPF52]

I suspect the bore is a bit tight, which will build pressure faster. It could be a result of minimal lapping on an economy barrel, since barrels are traditionally drilled tight, rifled, heat-treated, then lapped, if lapped at all.

For those that lap, the lapping process opens the land inner diameter. Most barrel makers use a lead slug that's embedded with lapping grit, and cycle the slug through the barrel until the desired finish and bore diameter is achieved.

The main issues I have are with publishing dangerous loads that are 320fps faster than they should be, then suggesting that it's because 5R rifling helps make a barrel faster. That was with the 2820fps 120gr TSX, and AA2520, which is literally 320fps faster than the fastest powder max load from industry-tested 24" barrels with the 120gr TSX. Then taking that data and concluding that it's a result of a special, fast barrel and running with it.

2820fps with a 120gr solid copper bullet is basically a max load or near max load in the .260 Remington, which I and many other forum members own, load, and shoot. The .260 Remington is a 60,000 psi SAAMI cartridge, and uses charges of even slower-burning powders with 42.7gr - 44.5gr weights to generate 2800fps. All it takes is pressure to get those speeds, so it looks like XCR was at least at 60,000 psi with that 120gr TSX load, maybe even higher.

What we did, instead of what is done on many other forums where a new reloader is insulted and basically trashed so they don't want to ever log on again, was try to find out what the details were behind the charge weight and powder type. Once I saw what the load and powder was, I asked what starting load he had worked up from before he hit 2820fps. To my shock, no starting load was ever used, just that max load of AA2520 that was developed for a cup & core 120gr bullet-not the TSX.

This highlights the importance of some basic reloading principles:

* Have a good source of reloading data for your specific bullet, case, primer, and powder.
* Know your maximum COL in your chamber with the bullet you're using.
* Have a good starting load, usually 10% lower than the maximum listed load. Ex: max load = 31.2gr, start load should be 28.1gr

...........( 31.2 x .10 = 3.12, 31.2 - 3.1 = 28.1)

* Know what pressure signs to look for, and how they start to show up (erratic velocities, expanded case heads above the extractor groove, loose primer pockets, etc.)
* Understand what types of powder are temperature sensitive, and at what temp increments you will start to see noticeable velocity changes.

There is nothing wrong with being new to reloading. We all were or are at some time. For guys like Drifter, LR1955, JASmith, and many other members of the forum, some of them were new to reloading before Reagan took office in 1981, and have been active hand-loaders since.

Many of us have experience with loading for the AR15 and AR10 already, as well as bolt guns and hand guns. In my case, I learned to reload on the .308 bolt gun, then went to AR10 in .308, .260 Remington, 6.5 Grendel, .223 AR15, .270 Winchester, and .40 S&W. I started with knowledgeable mentors who had been reloading for at least a decade per, and had more than a box of rocks for brains. Some people mysteriously escape the Darwin awards, riding multiple stacked factors of safety built-in by the industry, but eventually they will have an appointment with Mr. Murphy.

Our goal is to make sure that doesn't happen.

[Bill Alexander]

Bill Alexander claimed 5R barrels were slower and we needed to add powder to make up the dropped velocity.

As your determination seems to pick a fight and I lack the time to explain fully.

Please read the quote carefully and think about the context of the whole post. 5R barrels within a specific pressure level will allow faster velocity that is why the competition guys love them (they shoot good groups as well). Good lapping will also help for the same reason by allowing the bullet to move easily down the bore. For a given load they will drop the pressure and consequently the velocity. Bring them up to spec and they are fast.

I need +$40k of kit to examine the pressure. Typical load data takes a day at least and a few hundred round. If the results look shaky we cross reference with other manufacturers and provide loads and even reference ammunition to check the results. The whole process may take several weeks are you sure you can do this by eye over five round groups?

Do you not think that we have never encountered 5R rifling or polygonal or ratchet or gain twist or Enfield. That we have not tested multiple permutations of throat and neck design? We do not own adequate kit to quantify a barrel? Lap barrels or measure them mechanically and optically to the 5th decimal.

Polygonal form rifling (BHW makes excellent examples of this and fine barrels) extends the logical progression of 5R. It will drop the pressure slightly more and so you get a slight reduction in velocity.

So the "results" using the term in the broadest sense.

5R unlapped Liberty, most pressure fastest, variable throat and bore fouling so pressure jumps the most and the ES is up.
5R lapped, Very consistent bullet moves a little easier drops a bit of MV nice ES
Polygonal, Smooth, lowest engraving force and least bore resistance, slowest. (good barrel for hand loads that might well allow some improvement over factory velocities)

You did not use a correct standard pattern bore with known cross sectional area for the base line nor was testing controlled to STP. The sample set is not statistically valid. However with all this in mind your enthusiasm for shooting and a zest for knowledge is great. I can do nothing but commend your ideas and your contribution. The testing did show that there is merit in the BHW polygonal pattern and this might well be a great idea in a work carbine. Proof would require much more work but the foundation has been shown. Satern 5R demonstrates that it is a superb barrel as always.

[XcountryRider]

I suspect the bore is a bit tight, which will build pressure faster. It could be a result of minimal lapping on an economy barrel, since barrels are traditionally drilled tight, rifled, heat-treated, then lapped, if lapped at all.

For those that lap, the lapping process opens the land inner diameter. Most barrel makers use a lead slug that's embedded with lapping grit, and cycle the slug through the barrel until the desired finish and bore diameter is achieved.

The main issues I have are with publishing dangerous loads that are 320fps faster than they should be, then suggesting that it's because 5R rifling helps make a barrel faster. That was with the 2820fps 120gr TSX, and AA2520, which is literally 320fps faster than the fastest powder max load from industry-tested 24" barrels with the 120gr TSX. Then taking that data and concluding that it's a result of a special, fast barrel and running with it.

OMG dude why does he keep bring up a load that has nothing to do with this thread? He knows i backed off from 30.2gr to 29.3gr of AA2520 and keeps on bringing it up. I stopped reading after this just to much butt hurt preaching.

[XcountryRider]

As your determination seems to pick a fight and I lack the time to explain fully.

Please read the quote carefully and think about the context of the whole post. 5R barrels within a specific pressure level will allow faster velocity that is why the competition guys love them (they shoot good groups as well). Good lapping will also help for the same reason by allowing the bullet to move easily down the bore. For a given load they will drop the pressure and consequently the velocity. Bring them up to spec and they are fast.

I need +$40k of kit to examine the pressure. Typical load data takes a day at least and a few hundred round. If the results look shaky we cross reference with other manufacturers and provide loads and even reference ammunition to check the results. The whole process may take several weeks are you sure you can do this by eye over five round groups?

Do you not think that we have never encountered 5R rifling or polygonal or ratchet or gain twist or Enfield. That we have not tested multiple permutations of throat and neck design? We do not own adequate kit to quantify a barrel? Lap barrels or measure them mechanically and optically to the 5th decimal.

Polygonal form rifling (BHW makes excellent examples of this and fine barrels) extends the logical progression of 5R. It will drop the pressure slightly more and so you get a slight reduction in velocity.

So the "results" using the term in the broadest sense.

5R unlapped Liberty, most pressure fastest, variable throat and bore fouling so pressure jumps the most and the ES is up.
5R lapped, Very consistent bullet moves a little easier drops a bit of MV nice ES
Polygonal, Smooth, lowest engraving force and least bore resistance, slowest. (good barrel for hand loads that might well allow some improvement over factory velocities)

You did not use a correct standard pattern bore with known cross sectional area for the base line nor was testing controlled to STP. The sample set is not statistically valid. However with all this in mind your enthusiasm for shooting and a zest for knowledge is great. I can do nothing but commend your ideas and your contribution. The testing did show that there is merit in the BHW polygonal pattern and this might well be a great idea in a work carbine. Proof would require much more work but the foundation has been shown. Satern 5R demonstrates that it is a superb barrel as always.

Great explanation Bill!! Kind of matches the results.

[LRRPF52]

OMG dude why does he keep bring up a load that has nothing to do with this thread? He knows i backed off from 30.2gr to 29.3gr of AA2520 and keeps on bringing it up. I don't like Social Media consultants.......

The 2820fps load was one of the main contributors to the thinking that your barrel produces remarkable velocity. It's not a hit on you, but an important factor in the discussion. I am not a "Social Media Consultant". Not sure where you're getting that from, but I can assure you that it is 100% false information.

[XcountryRider]

When your shooting solids velocity is King and one reason why folks like the 6.8SPC because they have the higher velocity early in the trajectory. Solids make an excellent pig bullet because they pierce the armor before expanding. The Liberty barrels with the extra velocity make a good hunting option because you can get 2560-80fps with a 18in barrel no problem with a 120gr Barnes TSX and thats staying inside the Hornady reloading recommendations. I don't recommend the 24in barrel for hunting though because its to heavy to pack around. You can put together a Grendel with a 18in-20in Liberty barrel is the 8lbs to 9lbs range. My 18in Grendel loaded with 100gr Nosler BT gets 2700fps loaded with 30.5gr of H335. Thats right at what 6.8SPC gets from an 18in barrel when loaded to safe pressures. That velocity follows the same path as a a 308 168HPBT so works with my 308 turret on my Redfield Battlezone scope. Is it going to win a 1000 yard shooting competition? No but i'm not planning on shooting 1000 yards with it. Its my hunting stick. The 24in barrel is my sons.

[XcountryRider]

The 2820fps load was one of the main contributors to the thinking that your barrel produces remarkable velocity. It's not a hit on you, but an important factor in the discussion. I am not a "Social Media Consultant". Not sure where you're getting that from, but I can assure you that it is 100% false information.

An the AR Stoner barrel is not made in sweat shops in the PI or going to explode using factory loads.......

[Tedward]

Thanks for the summery Bill A. Just what you stated is exactly what I was interpreting out of the end results of this trend. The explanation of the lapping is a GREAT point and makes more sense now with the consistent speeds for consistent accuracy. Lapping resulting in the smooth slick consistent ride thru the tube...

All in all the end result of the trend really brings to light the difference in barrel types and when you want the sharp shooter or the woods hunter, there is a barrel for each application. No need to spend the extra dollars if that is not your goal and vise versa, don't expect 1/2moa out of and inexpensive barrel mass produced barrel, you do get what you pay for and the difference in price may be double but the wait might be even more.

Thanks XCR and Everyone for the input and all of the back & forth has helped me understand more about the rifling than I imagined.

[PA_Allen]

Thanks XCR and Everyone for the input and all of the back & forth has helped me understand more about the rifling than I imagined.

Tedward,
Here is a good read on Rifling and barrel manufacturing techniques.

http://riflemansjournal.blogspot.com/201...arrel.html


Mr Salazar knows his stuff; his blog is a wealth of knowledge.

Best,
PA_Allen

[Tedward]

Tedward,
Here is a good read on Rifling and barrel manufacturing techniques.

http://riflemansjournal.blogspot.com/201...arrel.html



Mr Salazar knows his stuff; his blog is a wealth of knowledge.

Best,
PA_Allen

Thanks, I had read that a week or so ago and yes it is good info. I have it saved to my favorites for reference purposes.....

[XcountryRider]

My new project is to see how accurate i can get with my button rifled Liberty. I added a bipod to my 18in and another ones coming in the mail in the morning. I'll be out of town this week and have the annual hunting trip at the end of the month but hopefully i can get some range time in.

[XcountryRider]

Looking at my notes i understated the 100gr Nosler data (30.5gr H335) in my 18in i cronyed 3 rounds and they were 2775, 2750 and 2793. Thats a pretty large ES as well. The ES in my 18in was better using the 123gr Amax with 2554, 2551 and 2555fps which is pretty good. .

[LRRPF52]

Looking at my notes i understated the 100gr Nosler data (30.5gr H335) in my 18in i cronyed 3 rounds and they were 2775, 2750 and 2793. Thats a pretty large ES as well. The ES in my 18in was better using the 123gr Amax with 2554, 2551 and 2555fps which is pretty good. .

That load is close to what Hodgdon's lists as max safe loads in a 20" barrel, with an average of 2744fps. So you're getting faster than a 20" barrel, with evident erratic velocities with only 3 samples. That's evidence of excessive pressure, and makes me think even more that you have a tight bore. The question then becomes, how much more pressure than 49,700psi did you hit to exceed 20" velocity with .2gr less powder? I would dial that one down as well. Think again about me when I saw the chrono spitting out 2580fps from my 16" with a 123gr factory load, but with erratic ES close to 100fps. It would have been awesome if it was stable, but it wasn't.

Hornady's 9th Edition data for an 18" barrel shows a max safe load of 29.6 grs of H335 under 100gr going 2650fps.

If you mean the factory 123gr A-MAX, then those 3 samples are definitely in the range you want, but with a larger sample, like a 10-round string. If the ES stays in the singles or low doubles, you have a good longer range load right there with the factory A-MAX, which is also an amazing hunting bullet in the real world. It expands extremely well, retains weight well, and penetrates well...consistently.

[calshipbuilder]

Thanks XCR and Everyone for the input and all of the back & forth has helped me understand more about the rifling than I imagined.

This +1

Also, XCR, your barrels might be a good test set for fire lapping. I wonder what the before and after would look like on velocity / accuracy:

\http://www.davidtubb.com/ff-kit-264-6-5mm-cal

[XcountryRider]

That's evidence of excessive pressure, and makes me think even more that you have a tight bore.

Remember we are talking about 2 rifles and not just one.