Grendel vs 308

[sneaky one]

Bigbear98, As to -on game performance between the .308 , & the Grrr.= I have owned both, shot whitetail w/ both. The ballistics speak well of the expected on game results. The Grendel is - basically , a 2/3rds of performance on game kills, as compared to .308.

Always wanted a .260 since it's inception, in the 90's. I'm glad that I waited a decade , for my first 6.5 rifle tho.. The mighty Grrr rocks.

Could not be happier , here. I have since sold the .308- to my fave BIL. He's also a happy guy.

My family was always big .30 cal. guys. - Less is really more , on hunt rifles lately, if shots are under 3-400 yds.

My thoughts are - I may want a super lite wt. Grr bbl.

A few of us are exploring new wts. for the bullets for Grendel whitetail hunting apps. Only half way thru the details, more to follow.

The .308 does a fine job as a game getter in range, yet,, it's not as cool as the Grrr...

[bigbear_98]

I am amazed that learning how to true ballistic calculators has made such a huge difference for me. I surprise and impress myself and my shooting partners when we go to the range now, and its just a matter of having good data.

LRRPF52 You answered a lot of questions posted in this thread in your post. Thanks.

sneaky one, I have been very happy with the way my grendel performs. It surprises me. Sometimes I say to myself, "no way I just hit that".

[NugginFutz]

bigbear_98. It's not too late - join us in Utah, this week! LRRPF52 promises to open our eyes in several ways. 3 days, and counting...

[bigbear_98]

After looking at the Lija 20" velocity thread, I think my krieger is right in line with the velocities everyone else is getting with 20" barrels and factory sst.

Utah is a pretty big trek to just decide to go for the weekend. Y'all let me know what you learn. Post an aar.

[waveslayer]

After looking at the Lija 20" velocity thread, I think my krieger is right in line with the velocities everyone else is getting with 20" barrels and factory sst.

Utah is a pretty big trek to just decide to go for the weekend. Y'all let me know what you learn. Post an aar.

Quick Flight on AA and you will be in SLC, rent a cheap car and make the almost 2 hour drive south to Price. You will love it.

[bigbear_98]

Soo.... I guess I have some crow to eat here.....

I took my rifles out and shot Friday at 250,500,750,and 1000. Both rifles were rocking steel at all distances, until I tried to shoot the Grendel at 1000. Now I went back to my data, compared the whiz wheel with my Ballistics app, both said 41.5 minutes of elevation, but I really needed 44 minutes.

Well, This bothered me. I switched back to my 308 and shot. I found things on the berm to shoot. Lazed them, looked at the chart, dialed the elevation, boom and hit. This was true data here. The 308 data was on. 250, 254, 500, 508, 745, 750, 755, 1000, 1008. Everything I aimed at I could hit with the 308. good numbers.

Ok go back to the Grendel and try to refine it as I did the 308. 250, 500 good... Wait was That a little low? Yes. So I ran everything all over again. I ran a box test on my scope. Good data there. tracks a little off at the high end but not bad and I can account for it. (Vortex PST)

So then I Shot at all distances I could. Took note of the elevation that It actually took to be zeroed at that distance, and compared to the numbers I already had. Well It was different. Close, but different.

I then set my chrono back up at 200 yards. Same number.

So I start to play with the BC of the bullet. I ran it down.... Way down.... And got the numbers on paper to match what I was really seeing. I kept the 200 yard velocity the same, lowered the BC, and raised the muzzle velocity.

Now I did all of this at a 3000 DA, so I am curious to see if it changes with the atmosphere, but It is exactly true right now. It is so true that, believe it or not, I couldn't miss with elevation. Wind was light, but enough to push 1-2 minutes, but elevation was perfect.

[bigbear_98]

Edited to clean up the thread. The numbers are posted in post #44

[cory]

Soo.... I guess I have some crow to eat here.....

I took my rifles out and shot Friday at 250,500,750,and 1000. Both rifles were rocking steel at all distances, until I tried to shoot the Grendel at 1000. Now I went back to my data, compared the whiz wheel with my Ballistics app, both said 41.5 minutes of elevation, but I really needed 44 minutes.

Well, This bothered me. I switched back to my 308 and shot. I found things on the berm to shoot. Lazed them, looked at the chart, dialed the elevation, boom and hit. This was true data here. The 308 data was on. 250, 254, 500, 508, 745, 750, 755, 1000, 1008. Everything I aimed at I could hit with the 308. good numbers.

Ok go back to the Grendel and try to refine it as I did the 308. 250, 500 good... Wait was That a little low? Yes. So I ran everything all over again. I ran a box test on my scope. Good data there. tracks a little off at the high end but not bad and I can account for it. (Vortex PST)

So then I Shot at all distances I could. Took note of the elevation that It actually took to be zeroed at that distance, and compared to the numbers I already had. Well It was different. Close, but different.

I then set my chrono back up at 200 yards. Same number.

So I start to play with the BC of the bullet. I ran it down.... Way down.... And got the numbers on paper to match what I was really seeing. I kept the 200 yard velocity the same, lowered the BC, and raised the muzzle velocity.

Now I did all of this at a 3000 DA, so I am curious to see if it changes with the atmosphere, but It is exactly true right now. It is so true that, believe it or not, I couldn't miss with elevation. Wind was light, but enough to push 1-2 minutes, but elevation was perfect.

I'm completely lost here. Eating crow on what exactly? What bullet (BC) were you using with what muzzle velocity? What did you have to change the BC and MV to?

The intent of this thread seems to be a passive aggressive shot at the Grendel.

If I'm wrong I apologize, If not man up and say what you want to say. I don't care for passive aggressive double talk.

[bigbear_98]

Edited to clean up the thread. The numbers are posted in post #44

[bigbear_98]

I'm completely lost here. Eating crow on what exactly? What bullet (BC) were you using with what muzzle velocity? What did you have to change the BC and MV to?

The intent of this thread seems to be a passive aggressive shot at the Grendel.

If I'm wrong I apologize, If not man up and say what you want to say. I don't care for passive aggressive double talk.

Not at all being passive aggressive. Never will I be. I try to say what I think. I am eating crow because in previous posts I stated that my data was right. When if fact it wasn't.

I love this rifle. I am just sharing my info. I can stop if it hurts feelings.

[BluntForceTrauma]

Let his data stand and we'll see what he's got. If nothing else, we can all learn something. Shooting at long range has a zillion micro variables.

For example, you can throw a football with a perfect spiral and it flies beautifully. But throw it badly and it wobbles like a duck. Same with bullets. If your barrel puts a beautiful spin on your bullet, it'll fly far and true. If your spin is less than perfect your bullet will wobble slightly and its frontal area will effectively increase, reducing the BC. Just an example of things that can account for performance differences between barrels.

[cory]

Not at all being passive aggressive. Never will I be. I try to say what I think. I am eating crow because in previous posts I stated that my data was right. When if fact it wasn't.

I love this rifle. I am just sharing my info. I can stop if it hurts feelings.

No need to worry about hurt feelings. It just came across as trying to demonstrate that the Grendel has no business being compared the .308, without outright saying it, in what has been an apples to oranges comparison.

Again I apologize if I'm wrong.

You're talking factory AMAX correct? There's a lot of Grendel guys with a lot of experience with this load. If your finding the BC to be off significantly, I'd look for a problem with your barrel, starting with your crown. What ballistic app are you using and what are your inputs? It may just be your ballistic app is off. What do you think your MV is and how confident are you in it?

[bigbear_98]

DON’T TAKE ANYTHING FOR GRANTED! The bottom line is to deal in absolute fundamentals, measure them, and remove all the assumptions. Don’t ever assume that something is what it says without measuring it. – Bryan Litz, Applied Ballistics for Long-Range Shooting


I took my information for granted. I had ordered a whiz wheel from Accuracy first after taking their class and getting what I thought was good data. I used the 123gr sierra match king as a reference to get my BC. It was what they told me to use, and it was pretty good. I have since refined what I see as good.

During this class I was having scope trouble. The scope at the time wasn't tracking true, I was uncomfortable behind the rifle, and the classroom provided Kestrel I was using kept crashing. I took the data that I had gathered from the class, thinking it was correct, and used it. It has been close up to 750 yards but not perfect. I jumped the gun so to speak by posting what I did in the beginning of this thread. I was only showing what I had thought was my real data.

I have shot a lot of rounds and hate being wrong. And when I'm wrong I like to fix the problem, find out what it was, and share my findings.

[bigbear_98]

The bullet I am shooting is the SST. Ballistic AE is the app. My barrel shoots well. I am not getting wild groups or flyers. I sat two chronos up at 200 yards and shot through them to get the numbers I have.

I understand that this information combined with the comparison to my 308 seems as if I am trying to tear the round down. I have spent a lot of money on my rifle, and a lot of time shooting. Enough that I want this round to be successful.

I shouldn't have posted the 308/ Grendel I suppose. I just don't own a shorter 308, or longer Grendel to compare.

[bigbear_98]

Here is a comparison between the two. Notice how little difference there is until you get to close to 1000. This is where I was confused until I shot little things from far and measured them. Would you be able to see the difference by just measuring the group in the scope?


Edited to clean up the thread. The numbers are posted in post #44

[NugginFutz]

Something wrong with the data vs. column information alignment, in this last post. Short one column of data, it appears. Time values are zeroed, as well as going negative. (Inverse time? Bullets arrive prior to being fired?)

Perhaps when LRRPF52 reformatted the data, it got lost in translation.

[bigbear_98]

This is only showing the difference in drop between the two charts. The complete ballistic charts are in previous post.

[NugginFutz]

Thanks for clearing that up. Still a little tired from the week's festivities.

[LRRPF52]

From the shooter perspective in my case in the same shooting area and almost identical conditions, I have made similar shots with both the .308 22" bolt gun spitting 175gr SMK's (1118yds), and 123gr A-MAX from my 16" AR15 carbine (1200yds).

Bryan Litz put out an extensive series of articles, as well as two excellent books on long range applied ballistics, and he valued the G7 model for the 175gr SMK at .243

iSnipe lists the 123gr A-MAX at .256

Atmospherics and temps are the same for the following comparisons, basically sea level at 59 F. .308 will almost always have an energy advantage if comparing bullets with similar BC's shot at the same speeds. Hornady's 9th shows 2500fps as max for a 22" bolt gun .308 with 178gr, and 2500fps with the 123gr 6.5mm from an 18" Grendel, considering that the 120gr GMX limited them in the speeds due to start pressure of a solid and its longer bearing surface.

What I get out of this is that my supersonic reach is a bit farther, my powder consumption is significantly less, recoil is around half, and the Grendel works out of an AR15, purpose-built for an AR15. When I was shooting .308, I only hand-loaded since I was shooting gas guns, and the 168gr sucks as a long range bullet, whereas the 175gr loads are optimized for bolt guns with no gas system.

6.5 Grendel 123gr A-MAX at 2500fps mv

Code:

Range Velocity Energy Trajectory TOF Drift (yards) (fps) (ft-lb) (MILS) (sec) (MILS) 0 2500 1707 0.00 0.0000 0.00 50 2414 1592 -0.00 0.0611 -0.10 100 2330 1483 0.00 0.1243 -0.21 150 2247 1379 -0.30 0.1898 -0.32 200 2167 1282 -0.68 0.2578 -0.44 250 2088 1190 -1.12 0.3283 -0.56 300 2010 1103 -1.60 0.4015 -0.68 350 1934 1022 -2.11 0.4776 -0.81 400 1860 944 -2.65 0.5567 -0.94 450 1786 871 -3.23 0.6390 -1.08 [B]500 1715 803 -3.85 0.7247 -1.22[/B] 550 1644 738 -4.50 0.8140 -1.37 600 1575 677 -5.19 0.9072 -1.53 650 1507 620 -5.93 1.0046 -1.69 700 1440 567 -6.71 1.1064 -1.86 750 1375 517 -7.54 1.2130 -2.04 [B]800 1312 470 -8.43 1.3247 -2.23[/B] 850 1250 427 -9.38 1.4419 -2.43 900 1190 387 -10.40 1.5649 -2.64 [B]950 1134 351 -11.48 1.6941 -2.85[/B] 1000 1087 323 -12.65 1.8294 -3.08 1050 1056 305 -13.90 1.9697 -3.31 1100 1032 291 -15.24 2.1135 -3.53 1150 1012 280 -16.65 2.2604 -3.75 1200 994 270 -18.15 2.4102 -3.96

.308 175gr SMK at 2500fps mv

Code:

Range Velocity Energy Trajectory TOF Drift (yards) (fps) (ft-lb) (MILS) (sec) (MILS) 0 2500 2429 0.00 0.0000 0.00 50 2410 2256 -0.00 0.0611 -0.11 100 2321 2093 -0.00 0.1245 -0.22 150 2234 1940 -0.30 0.1904 -0.34 200 2150 1795 -0.69 0.2588 -0.46 250 2067 1660 -1.13 0.3300 -0.59 300 1986 1532 -1.62 0.4040 -0.72 350 1906 1412 -2.14 0.4811 -0.86 400 1828 1298 -2.69 0.5615 -1.00 450 1752 1192 -3.29 0.6453 -1.15 [B]500 1677 1092 -3.92 0.7328 -1.30[/B] 550 1603 999 -4.59 0.8243 -1.46 600 1531 911 -5.31 0.9200 -1.63 650 1460 829 -6.08 1.0204 -1.81 700 1391 752 -6.90 1.1256 -2.00 750 1324 681 -7.77 1.2361 -2.19 [B]800 1259 616 -8.71 1.3523 -2.40[/B] 850 1196 555 -9.72 1.4746 -2.62 [B]900 1136 501 -10.80 1.6034 -2.85[/B] 950 1086 458 -11.97 1.7387 -3.08 1000 1054 432 -13.22 1.8791 -3.32 1050 1029 412 -14.56 2.0232 -3.56 1100 1009 395 -15.99 2.1706 -3.78 1150 990 381 -17.50 2.3209 -4.00 1200 972 367 -19.09 2.4740 -4.22

[cory]

The bullet I am shooting is the SST. Ballistic AE is the app. My barrel shoots well. I am not getting wild groups or flyers. I sat two chronos up at 200 yards and shot through them to get the numbers I have.

I understand that this information combined with the comparison to my 308 seems as if I am trying to tear the round down. I have spent a lot of money on my rifle, and a lot of time shooting. Enough that I want this round to be successful.

I shouldn't have posted the 308/ Grendel I suppose. I just don't own a shorter 308, or longer Grendel to compare.

I'm happy to eat crow here. Now let's figure out what's going on, and get you squared away.

Have you tested your current scope to make sure it's tracking true?