18" AR velocity

[jLorenzo]

Found the node sort of for my 18" AR, 23.6 great Varget loaded to mag length with Hornady 75gr BTHPs, this gun is meant to shoot out to 700. I'm only getting around 2530. Is that strangely low? My gun seems to like slower stuff being a gas gun. 23.6 and 23.8 are negligible. Will shoot some some groups in the .8s then open up to 1.2-1.3 and not necessarily in that order. Been using LC brass from bulk Wal mart American Eagle 55gr 5.56. Just received 200 pieces of once fired matching year LC online aND a batch of 250 75gr bthps. Any ideas on what to try?

 

[TonyTheTiger]

Try 8208 in the same 23.4-23.8 charge range. Its a known node with 75/77's and should get you around 2700fps give or take.

 

[Steel head]

Try 8208 in the same 23.4-23.8 charge range. Its a known node with 75/77's and should get you around 2700fps give or take.

That’s a good place with 8208.

 

[AMGtuned]

I get 2600 average and SD of 11 with 24.1 Varget, 69gr smk, mixed LC brass, 16" tube

 

[jLorenzo]

I'm thinking a WOA barrel is in my future. It's just a PSA A2 stainless 1/7 .223 wylde. Seemed like a decent barrel that came on a complete upper. Just have not been able to find a load that shoots CONSISTENTLY at 1 MOA. It has shot some great groups and some bad ones. Seems to be stable around 1.2-1.3 MOA which at 700 starts to show.

 

[jLorenzo]

Are 8208 and 8208 XBR one in the same or different?

 

[TonyTheTiger]

Are 8208 and 8208 XBR one in the same or different?

Same thing.

 

[RTH1800]

I did a good bit of testing on 18" AR barrels with the 77 SMK.
Fastest load with good accuracy was with Ramshot TAC. Various barrels ran from 2680 to 2820 at 70 deg. Douglass barrels were second in speed and Proof first. I tested A LOT of different barrels.

 

[jLorenzo]

I did a good bit of testing on 18" AR barrels with the 77 SMK.
Fastest load with good accuracy was with Ramshot TAC. Various barrels ran from 2680 to 2820 at 70 deg. Douglass barrels were second in speed and Proof first. I tested A LOT of different barrels.

Any kind of post about this or write up? Sounds interesting.

 

[RTH1800]

Sorry, I did not save data.

I was just seeking the best I could find for accuracy, velocity and clean killing.

Answer is as above. Get a 7 twist Douglas or PR. Both will hold 6” vertical at 600m for 5 shot groups. The fast twist seems to stress the bullets upon impact opening them up and transferring a lot of energy. Whatever the reason, the 7 twist barrels unquestionably kill better.

The other big name and lesser named barrels simply did not test as well in one or more categories. Multiple barrels were tried on most of the better known barrels.

In speaking with Alan Brown from Crane my results mirrored exactly the Navy testing for the Mk 12 project. I tested about 50 rifles/barrels. Navy test were more extensive of course.

 

[palmettoman]

I'm thinking a WOA barrel is in my future. It's just a PSA A2 stainless 1/7 .223 wylde. Seemed like a decent barrel that came on a complete upper. Just have not been able to find a load that shoots CONSISTENTLY at 1 MOA. It has shot some great groups and some bad ones. Seems to be stable around 1.2-1.3 MOA which at 700 starts to show.

Same experience for my PSA Wylde barrel. It was decent...just not good. I wasted alot of money trying to get it to shoot.

I bought an 18" WOA and it made a big, big difference. Accurate 2520 is what I've settled on for the 77SMK's. 25.2 gr. gets me 2700+.

 

[bunsen27]

I'm thinking a WOA barrel is in my future. It's just a PSA A2 stainless 1/7 .223 wylde. Seemed like a decent barrel that came on a complete upper. Just have not been able to find a load that shoots CONSISTENTLY at 1 MOA. It has shot some great groups and some bad ones. Seems to be stable around 1.2-1.3 MOA which at 700 starts to show.

Same experience for my PSA Wylde barrel. It was decent...just not good. I wasted alot of money trying to get it to shoot.

I bought an 18" WOA and it made a big, big difference. Accurate 2520 is what I've settled on for the 77SMK's. 25.2 gr. gets me 2700+.

I have two WOA 1 in 7" twist 18" SPR barrels and my go to sub MOA load is:

LC brass
WSR or CCI400
XBR 8208 = 23.1-2gr
77gr SMK at 2.248OAL
Velocity = 2650fps

The flyer was the last round locking back the bolt.