6.5 Grendel beyond 1k input needed.

[Steve390Gold]

Im running an AR15 with a 20" satern 5r cut barrel, spuhr 9.9mil base, burris xtrII 5-25. Handloads using 6.5mm 123gr, hornady eld-m at 2500fps.

She shoots beautifully to 1k without issue and held some phenominally small groups at 761 yards. (Strelok basic was also spot in to 1k with the dope.)

But when I attempted shots on the 1300 yard gong (fully subsonic) I discovered that I needed 3 more MILs (3.6mil iirc) than the ballistic software calculated. Is that normal for a transition into subsonic flight?

Unfortunately thay didnt have hit indicators on their 1k + targets so I was unable to see impacts very well either. Would a higher quality optic allow better resolution to see low energy impacts at 1300 and beyond (assuming minimal mirage)?

As I was anticipating, I was able to dial for all ranges and didn't have to use the reticle....

I do want to take this round to a mile and to that end have constructed some of my own hit indicators as well as currently working up a new load using berger 130s at ~2500.

What else am I going to need to be somewhat successful getting there?

PS - I am building a 300PRC which obviously will be much better at 1760., but I'd love to do this with the grendel first.

 

[nick338]

Did you actually verify an impact on the gong?

 

[Steve390Gold]

Yes I know for absolute certain I smacked it once as I saw a grey dot appear were none had been previously on the freshly painted gong. However I was unable to see any further hits.

That was my first time shooting beyond 630 yards as well. It was humbling for sure.

 

[Clearlight]

Barrel twist ? Maybe try a better solver if you can , like AB with the appropriate Custom Drag Curve .
Nearest thing I can relate to that is a mate running 225 ELDMs out of a Win Mag : once transonic , we
had to lower the BC quite a bit to true Strelok pro at 2100 yards .

 

[badassgunworks]

the 6.5 Grendel is not optimum beyond 1000 to 1100 yards so it wont be consistant unless you build it in a bolt action with a longer barrel and run higher bc heavier bullets hotter your just asking too much for a under under powered little round.

 

[Sticks]

I've been running the Grendel for a couple years now. We are without question handicapped by low starting velocity and projectile BC. Lot of testing and 123's are the optimum pill. If someone would come out with a .5 G1 115 grain pill, we would have a significantly better chance at the longer ranges.

I have an 18" Bartlien, 24" Lillja and 20" Howa. All three of them push the 2475-2500 with Factory and handload 123gr. (on the ragged edge of pressure). I've had some 130's running that well out of the Howa, and am still working on it. Could not get the accuracy dialed in. Thinking muzzle device needs changed.

After running the numbers, I spent a lot of time and money on the 130 development and really did not get any significant gains over the 123s. Once that pile is gone, back to the 123s. and keep working on the 1k shooting. Makes shooting my 6.5 PRC so easy.

 

[Ledzep]

Try the Hornady 4DoF app. In my experience it's done an excellent job exceeding the supersonic range. I've used it both for subsonic .30 cals which produced first round hits at 330yd (most solvers fall flat on their face with subs), and taking my 6.5 creedmoor out to ~1700yd I was within 2 tenths of the actual.

 

[AthlonOpticsGuy]

Anybody got a safe load for 120 gmx and varget? Mine is crunchy..

 

[badassgunworks]

I have a cartridge called the 6.5 ares fireformed from the 220 russin just like the Grendel but ultra improved I am running the 130 vld bullets at 2650 fps much better outcome at distance

 

[Strykervet]

When a bullet goes transonic you're gonna take on a lot more error into the subsonic range.

I used to nail the piss out of 600m E types with a basic issue M4 and an ACOG firing M855 but take that to 800m and now it's a probability question and less of a ballistic one. It can fall short, go over or off to either side but the only consistent thing is inconsistency.

Any environmental changes will also exacerbate this from day to day. So even if you figure out probability within that cone of fire it won't be the same data tomorrow.