stronger bolt material for high pressure loads??

[hidesert cowboy]

I was wondering if there is a stronger material grendel bolts could be made of that would allow high pressure loading up to say 65k psi. The lower pressure is to me what handicaps the grendel. it would have to be something other than 9310 or capenter 158, any idea what speeds could be had with 123's if you could load up to 65k??

[Tedward]

Titanium but I think there needs to be a limit. Something will give or fail with all the pressure and then what?

[LRRPF52]

Titanium but I think there needs to be a limit. Something will give or fail with all the pressure and then what?

Are you serious? Titanium? You're doing this to torment me, I know it.

OP: If you call 1100yds still supersonic at sea level with a 123gr A-MAX from a 16" barrel handicapped, then I guess you could step up to a .260 Remington.

       Range    Velocity    Energy     Trajectory         TOF          Drift
      (yards)     (fps)     (ft-lb)       (MILS)         (sec)         (MILS)
          0      [B]2550  [/B]      1776           0.00         0.0000         0.00
        100      2378        1545           0.00         0.1218        -0.21
        200      2213        1338          -0.51         0.2526        -0.42
        300      2055        1153          -1.34         0.3932        -0.66
        400      1903         989          -2.32         0.5449        -0.91
        500      1759         845          -3.45         0.7089        -1.18
        600      1623         720          -4.72         0.8864        -1.47
        700      1497         612          -6.15         1.0789        -1.79
        800      1381         521          -7.77         1.2876        -2.12
        900      1279         446          -9.59         1.5135        -2.47
       1000      1190         387         -11.63         1.7570        -2.84
       1100      1117         341         -13.93         2.0177        -3.22

My 22" .260 Remington AR10 will push the same 123gr A-MAX to 2915fps. At 200yds, it has slowed down to the muzzle velocity of my 16" Grendel, so 200yds of performance loss.

       Range    Velocity    Energy     Trajectory         TOF          Drift
      (yards)     (fps)     (ft-lb)       (MILS)         (sec)         (MILS)
          0      2915        2321           0.00         0.0000         0.00
        100      2729        2033          -0.00         0.1064        -0.17
        200      [B]2550[/B]        1775          -0.30         0.2201        -0.35
        300      2378        1544          -0.90         0.3419        -0.54
        400      2213        1337          -1.62         0.4727        -0.75
        500      2054        1153          -2.46         0.6134        -0.97
        600      1903         989          -3.39         0.7652        -1.20
        700      1759         845          -4.44         0.9291        -1.46
        800      1623         720          -5.62         1.1067        -1.73
        900      1497         612          -6.94         1.2993        -2.03
       1000      1381         521          -8.44         1.5080        -2.34
       1100      1278         446         -10.12         1.7340        -2.68
       1200      1190         387         -12.01         1.9775        -3.03
       1300      1117         340         -14.14         2.2382        -3.39

My 16" Grendel with scope and magazine weighs 8.6lbs.

My 22" .260 Rem is 14lbs.

65k psi is .270 Winchester territory, and about 2/3 of the primers on the market will crater before you even hit 60,000psi. How far would you like to stay supersonic with a Grendel, or is it only about having more muzzle velocity for the sake of it, just to say, this thing cranks out at 2700-2900fps!

I was in the same boat years ago, until I shot my little 16" at 1200yds. Now I look for loads that have lower pressure, with an efficient powder that burns ideally for my gas system length, or I just shoot the Hornady 123gr A-MAX load, which is what I shot to 1200yds with.

[cory]

I was wondering if there is a stronger material grendel bolts could be made of that would allow high pressure loading up to say 65k psi. The lower pressure is to me what handicaps the grendel. it would have to be something other than 9310 or capenter 158, any idea what speeds could be had with 123's if you could load up to 65k??

Welcome to the party. This has been discussed a few times. Until someone brings Adamantium to the market the 9310 steel is about as stron as you're going to get for a bolt.

At 65ksi you're talking magnum pressures, I think you meant the 60ksi that the 5.56 and 308 are pushed to.

Even if you can get a bolt that can handle that pressure, you're limited by the mag length of the AR15. To fit enough powder in the Grendel case you'll need to load to a longer COL than 2.3".

The Grendel needs a new platform to maximize it's potential. However, the gains you'll achieve don't really make it worth the investment of a new platform. That being said, the new DTA bullpup seems like it was designed for the Grendel.

[LRRPF52]

Like I said, you're looking at 200yds of performance difference between my 16" Grendel and 22" .260 Remington with the 123gr A-MAX, with both being supersonic past 1000yds at sea level still.

If you use a 22"-24" Grendel with LVR, you're looking at 90yds of performance difference than my 2915fps .260 Rem load with the 123gr A-MAX.

The .260 Rem is a 60,000psi SAAMI cartridge. .308 Winchester and 5.56 NATO are both rated by SAAMI to 62,000psi.

We should be trying to reduce peak pressure, not increase it. That's why I look closely at the rated PSI next to powders with the bullet, as well as the mv. Lower peak pressure plus longer burn time but not such that we hit the gas port hard is what you're looking for.

[Tedward]

Are you serious? Titanium? You're doing this to torment me, I know it.

I was just throwing something out there that sounds strong but no merit to it, just a chop buster

Yes i agree with what your saying though, go to another caliber in another platform. I was thinking the Creedmoor but again, not enough knowledge in the AR-10 yet. And I like the light weight AR-15 platform. AR-30??

[bwaites]

I was just throwing something out there that sounds strong but no merit to it, just a chop buster

Yes i agree with what your saying though, go to another caliber in another platform. I was thinking the Creedmoor but again, not enough knowledge in the AR-10 yet. And I like the light weight AR-15 platform. AR-30??

Go look at DPMS's new platform for 7.62x51.

[Tedward]

Go look at DPMS's new platform for 7.62x51.

http://dpms-gii.com/full.html#configurations

Now that is revitalizing the 7.63/308. 7.5 Lbs to 10.5lbs. Uses the 223 Free Float Hand Guard & Barrel Nut, lighter compact bolt carrier and much more. This is cool but parts will now be proprietary I would think.

[JASmith]

I am told that taking advantage of that level of pressure would require redesign of other parts of the receiver and bolt. Gets complicated real fast, which might explain why it hasn't been done.

Then, when one looks at the potential gain of less than 200 ft/sec pointed out by LRRPF52, then we see that the rest of the story includes minimal real performance increases.

[hidesert cowboy]

I would not call the performance increase minimal, when you only shooting 2500 fps if you add 200 fps your adding quite a bit, 200 fps is less of a big deal when your shooting something at say 3500 fps. the 270 winchester is rated for 65k psi if I am not mistaken, these specs are normally tied to the rifles that will likely be shooting them rather than actual capabilities of the brass, for example the 3006 should function in garand rifles, the 6.5x55 operates at a lower pressure because of the swedish mausers. 30-30 has to function and not damage lever actions.

as to cratered primers gre tan rifles deals with this by bushing the firing pin on bolt action rifles. if the firing pin hole is sloppy thats where your cratering problem comes into play. I am not saying you can load to 65k without issues, perhaps those that set the spec on the grendel felt that it would be too easily to spike well beyond that. but it seems like the pressures that the grendel is rated for is leaving some speed on the table. as a handloader I want all the speed I can safely get. if the problem is a weak bolt and a loose firing pin hole that sounds easy enough to correct.

[Trock03]

Just get you a Liberty barrel if you want higher pressures (very tongue in cheek).

[JASmith]

Several of us have run the numbers and there is truly not much to be gained by "souping up" the Grendel from where it is today. That 200 fps is just an 8% improvement. The added kinetic energy buys nothing in terminal performance. Impact on wind drift is hard to verify with the shooting skills most of us have. I will hasten to add that several of our forum members have those skills and do indeed use the Grendel to place high in and even win some long range competitions.

We already have factory loads that are deer-capable out to past 500 yards in most barrel lengths. Most of us should not consider a shot out that far, but the rifle will do it.

The only way to improve on the long range target performance is to minimize wind drift. One needs to go to the much larger 6.5 Creedmoor and magnum size cases to get enough reduction to make a serious difference.

So, would we grab extra velocity uf we can get it? Darned Tootin!

But, we also know it doesn't buy much beyond bragging rights unless one is engaged in upper-level long-range (600 - 1000 yard) target competition.

[LRRPF52]

The most real, tangible thing you can do to improve the 6.5 Grendel performance is...

...get out and shoot it.

[cory]

...But, we also know it doesn't buy much beyond bragging rights unless one is engaged in upper-level long-range (600 - 1000 yard) target competition.

Exactly. JA you're completely correct 200 fps doesn't buy us that much in performance, and the educated user knows that. However, it does buy bragging rights.

There's something to be said for the Ahh factor. However ridiculous it is, the Grendel's MV is thought of as being slow by a lot of people. (These are mostly those the ones who can't let the .308 go.)

200 fps may not mean much when hunting or target shooting, but 2600 fps + out of a carbine using 123gr pills can mean a lot in growing the Grendel brand. The more popular the Grendel is the more options we'll eventually get and eventually it'll bring costs down as more companies jump on board.

[LRRPF52]

The appeal to manufacturers is in the Grendel's lower pressures, SAAMI standardization, and larger margins in Factors Of Safety.

The performance speaks for itself once you look past mv, but I don't see the mv's as slow by any means. You can always go faster with more pressure, but at what costs.

If you push the pressures high, then you lose the Grendel throat right off the bat, and the accuracy life. Some guys with competition guns specifically built for one bullet shape don't have a problem with this, and it can be mitigated with melonited barrels, but for the average consumer who bought one for hunting, they would like some options in bullet selection, whether they are hunting large varmints like coyotes, taking down hogs with solids, putting some doe or buck meat in the freezer, or going after that larger game animal.

I used to be in the same boat asking for more and more mv, until I saw what the off-the-shelf cartridge does, even from short barrels. I no longer have any desire to hot-rod the Grendel, especially after seeing what CFE does for me under the 123gr.