I am currently shooting a Remington 700 ADL Varmint Special in .308 with a 1 in 12" twist 26" barrel. I shot the group shown below with a handload that is a 178 gr. Hornady AMAX over 43.2 gr.s of Varget. This group is a near duplicate of the same performance with FGMM 175's. I have chronographed the FGMM's and loaded the data in G7 and verified the drops at 200 and 300 yds. and repeated the exact same performance with the Hornady's. Supposedly the 175 and 178's will not stabilize in a 1:12 barrel. If I get this performance at 100(zero), 200 and 300 yards doesn't it stand to reason that the accuracy will be maintained to much greater distances?
-
Having trouble using the site?
Contact support
long range accuracy potential question
- Thread starter M60Jockey
- Start date
Seriously though, a 1:12 twist will stabilize 175’s, 178’s, 180’s both BTHP’s and VLD’s, 185 Berger hybrids and 190 berger VLD’s in my experience. This in barrels as long as 26” and as short as 20”... If you plan to go heavier some have even had luck with 208’s but I have not personally tried those yet...
Last edited:
I'm certainly a long ways away from being an expert and I'm not sure I really understand the answer you're looking for but here's my 2 cents.
Free reference tool http://www.bergerbullets.com/litz/TwistRuleAltWP.php
...and yes, the accuracy of the rifle should remain similar from 100 to 200 and 300 considering the angle/MOA. Then once the velocity gets to the area of being transonic you may lose some due to stability of the bullet/bullet design as it transitions to sub sonic.
Free reference tool http://www.bergerbullets.com/litz/TwistRuleAltWP.php
...and yes, the accuracy of the rifle should remain similar from 100 to 200 and 300 considering the angle/MOA. Then once the velocity gets to the area of being transonic you may lose some due to stability of the bullet/bullet design as it transitions to sub sonic.
Last edited:
Yep I just shot 178 amaxes in my r700 1:12" 26" barrel out to 750 and it was right at an 8" spread, and it was 8-12 mph 1/4 value wind basically the whole day with of course, winds natural tendencies to piss you off lol.
Here is a .566" group from 155gr lapua senars(which are nearly as long as the 178 amaxes). The shot not touching was a cold clean bore shot and there are 5 rounds in the lower group!
So keep on shooting bud! The 12" twist gets a lot of flak but in my opinion it's unjustified
Here is a .566" group from 155gr lapua senars(which are nearly as long as the 178 amaxes). The shot not touching was a cold clean bore shot and there are 5 rounds in the lower group!
So keep on shooting bud! The 12" twist gets a lot of flak but in my opinion it's unjustified
Thanks for the input. I did suspect that all of the BS about the 1:12 might not be 100% true. I am in the process of developing loads for the 700 -26" and my new 20" sps. I did notice on the Hornady b ox for the 178 AMAXs that it specificaly states that they are for a 1:10 twist. I put together a load out of the Hornady manual (43.2 gr.s of Varget) and took them out to test the theory and you see the result at 100. The drops came in line with the same data G7 provided for the FGMM 175's. I think this issue is settled for me. Next, I will try it with shorty - the sps.
FWIW, there will also be a faster node with varget in the 44-44.5 weight range. Lapua brass in my 308's tend to be 44-44.2 and winchestrer is 44.2-44.5... In my 20's this is right around 2550fps and the 43.2 would be around 2490ish. Running the same out of a 26 inch remington barrel will add 100 fps to each load.
I did load ten at 44.0 and the group blew up to 1 1/4"and the impact moved 1" right. Looked to me like I had a node at 43.2 and left it with the 44.0 charge weight. I will chronograph the 43.2 just to see what its really doing. I just got one of the Magnetospeed V2's and used it with he 175 GMM to set up drop tables and range cards. For any new load I usually go through the entire OCW drill, but on a whim pulled one load (43.2 varget) from Hornady and the 44.0 grain max from Lyman. Brass was once fired PMC from one of my "modern sporting rifles." I am holding my Lapua brass off until I settle on a pet load for each of the 700's. I am still wondering if the sub-moa and the predicted G7 drops will hold to 1000 yds. Mathematically, I don't see why they wouldn't.
It has for me, I dont recall ever needing more than a tenth or two of elevation (mil adjustments) to center it.
Your PMC brass likely has a different case volume than Lapua has so expect to adjust a few tenths of a grain when you make the switch. Winchester and hornady brass tends to require .2-.3 thenths more powder to center up in the node but I have not used PMC.
If you haven't tried any loads between 43.2 and 44.0 you may be doing yourself a favor to load several every .2 grains between. If you are jumping .8gr during load development your possibly leaving some accuracy on the table. As for twist I think you've got your answer.
You are right about the .8 gap. It was not an intentional load workup, more of a whim just to see if the 178's showed signs of instability. I will do a real OCW for the 178 AMAX before I decide to stick with anything. However, the fact that the 43.2g Varget charge just happened to exactly duplicate impact location on the targets, it also held about the same group size as the Federal GMM 175's. The chronograph will tell the tale. One other thing to consider velocity-wise is that I shoot at 4100 feet above sea level and higher. The FGMM 175 SMK chrono'ed at 2659 fps, which seems a little higher than literature and internet suggets.
Similar threads
