Grendel and 5R Rifling (Haters gonna Hate)

[bwaites]

No ones Ar stoner barrels are blowing up and they aren't made in sweat shops on the PI.

That would be rare. AR's are incredibly safe in their failure modes. Typically the bolt fails and pressure blows out the bottom of the mag well, disassembling the mag in the process. Have you seen or had that happen to you? I have, twice. Another time it happened while my wife was on the rifle. Fortunately, no one was injured because we were properly attired and the bench absorbed the mag contents. All three times were with old bolts, two in 5.56 with high round counts, once in a Grendel with an experimental bolt I was field testing and after several thousand rounds.

However, a 6.8 user had a much more catastrophic Kaboom when he inadvertantly used factory ammo that was too hot for his barrel, in a situation where a combination of manufacturing tolerances got stacked up.

The warning here is age old... If it seems too good to be true, it probably is!

[Drifter]

nevermind... I give up.

[lilharcher]

We may need to label all his future posts with a warning label so no inexperienced members get hurt from his "analysis" that goes beyond conventional wisdom.

[XcountryRider]

I talked to Steve Saturn and he fully expects 2650fps from a factory 123gr SST. Completely normal.

[Tedward]

After reading all of this back and forth Xcountry, that is a wide open statement. What weight bullet and what length barrel for that speed? I don't think anyone disagrees you can get that, just all of the factors come into play.

As I've read in all of this post, be safe, a lot of time has already been spent to come up with safe loads of powder and weight of bullets in length of barrels for safe fast shooting. If faster is desired, What I'm reading is, a different caliber is designed to do that.

A car might be able go 120mph but at 140mph it becomes unstable, doesn't mean its as safe. You can do it but one wrong thing and it can become a catastrophic failure.

[cory]

I talked to Steve Saturn and he fully expects 2650fps from a factory 123gr SST. Completely normal.

Brother, no one here is trying to make a fool of you. People here are legitimately worried about you.

Heed their advice and have a professional look at your weapon, please. I personally hope you're right, but the engineer in me knows you're to far above norm for something to not be right.

The horde is a unique forum. We don't attack people here, we all want to help each other. However, the personal attacks lately have been unusually high as they've been all but not existence. I hope it gets back to normal, soon!

I've trained in MMA as a hobby for a little while now. Whenever I talk to a friend that expresses interest in the sport, the first thing I tell them is check your ego at the door. If you don't, you won't learn anything and you'll likely get yourself injured or injure someone else. The same goes for here.

Added Analysis: Looking at the 5R design I do believe it could possibly give higher velocity as there is certainly less friction on the bullet. However, friction is a small factor in this equation, thus velocity gains shouldn't be significant.

[ricsmall]

Brother, no one here is trying to make a fool of you. People here are legitimately worried about you.

Heed their advice and have a professional look at your weapon, please. I personally hope you're right, but the engineer in me knows you're to far above norm for something to not be right.

The horde is a unique forum. We don't attack people here, we all want to help each other. However, the personal attacks lately have been unusually high as they've been all but not existence. I hope it gets back to normal, soon!

I've trained in MMA as a hobby for a little while now. Whenever I talk to a friend that expresses interest in the sport, the first thing I tell them is check your ego at the door. If you don't, you won't learn anything and you'll likely get yourself injured or injure someone else. The same goes for here.

+1. Xcountry, let some more folks with these pipes get some chrono info in before resuming with these loads. Im getting 2550 with factory amax in a 22" bartlein, which is 5R as well, so in a 24" your 2650 isnt too far off, but theres alot of experience here, lots of it from the university of hard knocks, and these guys are trying to steer you down the safe path. Sit back and soak in the knowledge, be safe, and have fun. Remember, a little velocity gain doesnt usually make much difference in external ballistics, but can make huge differences in equipment longevity and your personal safety. Post up some pics of groups shooting at "normal" velocities, and some with your handload velocities. How are the two comparing? Velocity isnt always king, but accuracy is.

Richard

Richard

[XcountryRider]

Hey guys you might have come to the conclusion that i'm running high unsafe loads if you just read this thread and not the various other discussions. I'm not running a load that giving me 2800fps from a 120gr barnes solid. I ran a few shots through of 30.2gr AA2520 a month or so ago and got that velocity and back off the load and dropped a gr of powder using Hornadys 120GMX load data as a reference. You can see it in thread. While i appreciate some of your concern those of you that are legit. This topic is not about my hand loads its about increased velocities from Liberty barrels. I had a nice conversation with Steve Saturn this afternoon. Several ammo makers use his barrels to test lots. hes gotten calls from them asking the same thing. The Liberty barrels are known to run fast. I'm not a barrel machinist or engineer so i'm not going to try and regurgitate all of what Steve Saturn said about his design. The short of it is that they are designed to be fast and 2650fps for a 123gr Amax is completely in the norm. There's no signs of pressure on the case or primer all is good. For those saying its the crony well it would need to be two cronys that only register higher velocities when pills are shot through from Liberty button 5R rifles barrels. As far as Bill Alexander saying that 5R delivers slower velocities just not buying that. The talk with Steve and Deb Saturn was enlightening and gave me some insight some not appropriate to share here on how some folks operate.

[XcountryRider]

We are going to shoot some Amax through 2 chronys tomorrow at the same time just to put a nail in that coffin. I'll post up the video when i get back.

[XcountryRider]

Brother, no one here is trying to make a fool of you. People here are legitimately worried about you.

Heed their advice and have a professional look at your weapon, please.

We have chronyed 3 Liberty barrels not just one and i talked to the manufacture and he says they are right at the velocity he expects to see. Nothing is wrong with the barrels.

[XcountryRider]

I went out with a couple Grendlers today and we shoot through 3 chronys at the same time. One 24in Saturn 5R cut rifle, one 24in BHW 264LBC 3L Poly, and one 24in Liberty 5R Button Rifle. The results pretty much confirmed what i thought. You can see the video below. Rickoshay took the notes. The Liberty Barrel was the fastest but I'd say the Saturn was the most accurate. My thoughts are for accuracy and velocity together the Saturn 5R is the way to go. For a hunting stick at a good price were velocity counts for bullet expansion then its the Liberty but cost is a factor here. Get the Liberty if you want a hunting stick at a decent price but if you got the coin get the 5R rifle cut Saturn. The 24in LBC 3 land Poly was the slowest but still had decent velocities in the 2625fps range but was also real accurate. Some of the velocities could be explained by the 94 degree heat and 3400ft elevation. The brass all looked pretty much the same with the Liberty barrel showing no more signs of pressure than the other brass from the other two barrels. Hopefully Rickoshay will chime in with his thoughts. All ammo was from the same box of factory 123gr Amax ammo to take differences in lot out of the equation. For accuracy its the Saturn first, BHW and the Liberty last. In defense of the Liberty its got a cheap scope so with a scope upgrade i'm sure it will have tighter groups. As in everything its the intended purpose and budget that drives the purchase decision.

[video=youtube;42Wci69BEbw]http://www.youtube.com/watch?v=42Wci69BEbw&feature=youtu.be[/video]

[rickOshay]

I can confirm that XcountryRider's (XCR) Liberty barrel rifle achieved higher average velocity than my Satern barrel and the .264 LBC BHW barrel. We all shot commercial 123 gr A-MAX from the same box, lot #8150. As XCR pointed out, it was very hot yesterday in the Southern CA desert - 97F, and we were at 3400 ft elevation. So all of our velocities were higher than advertised.

We shot through three chronographs simultaneously and the fps results for 5 shots were:

rickOshay - Satern 24" 5R cut rifled:
Magnetospeed: 2639 average, ES 10
F1 Chrony: 2636 average, ES 28
Beta Chrony: 2633 average, ES 19

XCR - Stoner/Liberty 24" 5R button rifled:
Magnetospeed: 2673 average, ES 53 (he had one shot that measured 2701 fps)
F1 Chrony: 2666 average, ES 43
Beta Chrony: 2647, ES 37

.264 LBC 24" 3 Poly BHW barrel:
Magnetospeed: 2641 average, ES 21
F1 Chrony: 2622 average, ES 15
Beta Chrony: 2615 average, ES 12

XCR's barrel is faster, but does show more ES.

None of the spent brass showed ejector marks. Many of them from all three guns had flattened primers which was expected given the conditions.

We have eliminated one of the three possible reasons for XCR's high velocities - his chrony readings are in agreement with others.

XCR is aware that his rifle may be producing higher pressures and may run into pressure issues earlier in load development, especially under extreme heat conditions. But there was no evidence on the spent brass of any higher pressures than generated by the other two barrels.

[XcountryRider]

Thanks for your input Rickoshay!!

[Drifter]

We shot through three chronographs simultaneously and the fps results for 5 shots were:

rickOshay - Satern 24" 5R cut rifled:
Magnetospeed: 2639 average, ES 10
F1 Chrony: 2636 average, ES 28
Beta Chrony: 2633 average, ES 19
overall average= 2636 fps with ES 19

XCR - Stoner/Liberty 24" 5R button rifled:
Magnetospeed: 2673 average, ES 53 (he had one shot that measured 2701 fps)
F1 Chrony: 2666 average, ES 43
Beta Chrony: 2647, ES 37
overall average= 2662 fps with ES 44

264 LBC 24" 3 Poly BHW barrel:
Magnetospeed: 2641 average, ES 21
F1 Chrony: 2622 average, ES 15
Beta Chrony: 2615 average, ES 12
overall average= 2626 fps with ES 16

XCR's barrel is faster, but does show more ES.

I added portions in red above.

Comparing the two 5R barrels (and assuming that my math is correct), the velocity difference between the Satern and AR Stoner (Liberty) was ~26 fps. The polygonal BHW was another ~10 fps slower.

The difference seems relatively normal, even between barrels of identical manufacture.

Those conducting the test could likely shed some additional insight, but if ammo was baking in direct sunlight at ~97ºF, it's not surprising that the last barrel ran the fastest and with the highest ES. (Even if that was not the case, the differences still seem insignificant.)

Without reviewing all of the details from this and other threads, it seems that the results from this small sampling are rather inconclusive in declaring a velocity king. And any of the extremely high speeds previously shared regarding the AR Stoner barrel were directly related to handloaded ammo.

So in summary, the primary takeaway is that this particular AR Stoner barrel runs somewhat predictably with factory ammo, but caution should be used with handloads (just as it should with any other barrel).

Correct, or am I overlooking something...?

[Tedward]

Your starting to nit pick Drifter.... Just leave it that this round the Stoner was faster. Take 2????

Next go around, the Stoner needs to go first. Either way the difference isn't so dramatic I would go out an buy a Stoner for 26fps, I already have one, but accuracy is more important then the speed advantage in this bout. Also I watched XCR and he was pretty fast at shooting and that probably has something to do with accuracy AND he was resting on his barrel on the bag and blocks of wood.... What is up with that XCR???? Free Float Barrel but since it was about speed, really doesn't matter... so I don't think the point was accuracy but speed and I think the point is taken and now you need to use cold ammo to prove you didn't have an advantage....


This is never going to end you do realize this

At least that what I think...

[XcountryRider]

Your starting to nit pick Drifter.... Just leave it that this round the Stoner was faster. Take 2????

Next go around, the Stoner needs to go first. Either way the difference isn't so dramatic I would go out an buy a Stoner for 26fps, I already have one, but accuracy is more important then the speed advantage in this bout. Also I watched XCR and he was pretty fast at shooting and that probably has something to do with accuracy AND he was resting on his barrel on the bag and blocks of wood.... What is up with that XCR???? Free Float Barrel but since it was about speed, really doesn't matter... so I don't think the point was accuracy but speed and I think the point is taken and now you need to use cold ammo to prove you didn't have an advantage....


This is never going to end you do realize this

At least that what I think...

This test validated previous tests and showed the cronys are accurate. I'm not going to round up the boyz again and keep the ammo in a cooler to show yet again the Liberty barrels are fast. My/Son's bipod actually gets here tomorrow and your right i was not shooting for a tight group i was checking velocity. That said i don't think i'll be getting rickoshays quarter sized 5 shot groups. Some people just aren't going to be sold and that's it period.

[rickOshay]

The goal of the experiment was to determine if XCR's Chrony was given good data. I think it is. We can rule out one of the three reasons for unexpected high velocities that BWaites enumerated back in post #120, page 12. That leaves either barrel length or pressure. I didn't measure his barrel, but it didn't look longer than 24". Finally, that leaves pressure. And that's what we've all been concerned about.

Drifter - I don't think we should average the Magnetospeed in with the optical Chrony', because its at the muzzle and typically reads 10 fps faster than optical chronys at 10ft distance.

I would average the two Chorny's to give:
Satern - 2634
Liberty - 2657
BHW - 2619

So, yes, the Liberty barrel is faster, but only by 23 fps. However, the Liberty did post the highest velocity of over 2700 fps. The Liberty was giving much higher ES than the other two.

Yes - I agree that many more trials would have to be done to provide good data. But I do think XCr's barrel is faster. I just don't know why.

[XcountryRider]

It shows the chrony is good which means the measurement of last week of Shawns Liberty barrel is good as well and it was 2655fps which matches my MV and also validates my 18in barrel MV of 2560 with 123gr Amax. I'm sure as more folks get chronys that own Liberty's and shoot factory amax as the standard we'll get more results. One question is just one batch fast or all Liberty's? Is it just the 18 and 24in barrels or are the 16in fast as well?

[Tedward]

Good reply guys. I agree and the next AR-Stoner barrel, even my 24", might be slower. Each barrel is cut differently, even same manufacture so point proven in my book too....

I live in Northern VA, Drifter is close in N.C. and Tackdriver is in Roanoke. I would be happy to meet up somewhere with some Grendel Forum guy's and make a day of shooting. Actually sounds like fun so if there is anyone interested, maybe start up a Trend to get some East Coast Folks together. Even Bill A is invited...

[rickOshay]

Good idea Tedward - go for it.