155's in a 308 gas gun

[Scarface26]

I ran across some rounds I'd loaded with IMR 4895 and Lapua scenar 155's and they shot incredibly flat - like 8 mils to 900 yards flat out of an 18" bbl AR. Has anyone else done this? Did this wear your barrel out faster than the standard 168/175 loaded like factory? I did not see any pressure signs.

Is this a fool's errand? If I'm looking for flatter should I just go with a 6.5 CM?

Final question: has anyone used the sierra 155's in this role? Asking because they're half the price of the scenar(s).

Thanks

 

[LRRPF52]

That was literally my competition load, 155gr Scenars, Lapua brass, about 2820fps from a 22” Obermeyer built by GAP back in the 2000s. It was such a reliable, super-accurate rifle that just put rounds where you wanted them to go.

.308 barrel life is so long due to bore volume relative to the case wall diameter, so they just keep trucking along, especially if you use the harder steels from Bartlein, Krieger, or Criterion.

I did go to .260 Rem though shooting 130gr Bergers from a Bartlein pipe, which is stupid-flat and less wind drift.

Reticle movement with the .308 is worse, but the .260 and 6.5CM also move enough to make self-spotting difficult.

 

[Scarface26]

That was literally my competition load, 155gr Scenars, Lapua brass, about 2820fps from a 22” Obermeyer built by GAP back in the 2000s. It was such a reliable, super-accurate rifle that just put rounds where you wanted them to go.

.308 barrel life is so long due to bore volume relative to the case wall diameter, so they just keep trucking along, especially if you use the harder steels from Bartlein, Krieger, or Criterion.

I did go to .260 Rem though shooting 130gr Bergers from a Bartlein pipe, which is stupid-flat and less wind drift.

Reticle movement with the .308 is worse, but the .260 and 6.5CM also move enough to make self-spotting difficult.

WRT the quality of steel in the barrel, mine's a LaRue, and I think he bought the patent from Hank Reardon for super steel that never wears out. and won't ever develop a carbon ring. It does shoot, though.

Thank you.

 

[tekmann2377]

After shooting a few different combinations in gas guns over the years, I also have come to prefer 150-155 gr class loads in AR platforms.

I have not had any adverse pressure signs, nor premature barrel wear. It seems easier on brass too. Either IMR 4895 or H4895 both work very well.

I have shot a bunch of the older Sierra 2155's, but haven't tried the newer 2156's (which do have a better BC, but are reportedly harder to tune). The 2155's are stupid easy to get to shoot no matter you load them over.

 

[isofahunter]

As stated above 150-155 is where the AR 10 shines IMO.

 

[reelserious]

I shoot 155 s all the time. 46 grain of varget goes 2925 from my 26 inch barrel. Shoots fantastic. Shoots great out of my AR 10 also

 

[wvfarrier]

Me too but in a 24"

 

[LRShooter101]

YES! Trying to push the "heavies" in a semiauto (anything above 170) usually results in over-gasing the system, if you are trying to maximize velocity/performance. The over-gasing causes all kinds of issues to include malfunctions and trashed brass. Shooting the lighter bullets like the 155, means less gas/back pressure, plus they shoot flatter. I have always run a 150-160 in my .308/7.62 gas guns with great results.

 

[MikeMiller]

155’s with H4895 is a great recipe in a gas gun. Before the heavies in 308 F TR class came about. We all ran 155’s

I use Varget for long barrel bolt guns and H4895 for gas guns in 308

 

[Scarface26]

155’s with H4895 is a great recipe in a gas gun. Before the heavies in 308 F TR class came about. We all ran 155’s

I use Varget for long barrel bolt guns and H4895 for gas guns in 308

10-4. I'm stuck with about 5# of the IMR variant so I'm on the hunt for some of the sierra 2155's.

 

[tekmann2377]

I wouldn't say you are "stuck" with the IMR 4895... It does have some temperature sensitivity but is forgiving to load with wide nodes, is not "peaky," and generates good velocity.

 

[Hetzer]

I run 155's with H4895 as well. I've been using/testing 42.5 grains and so far it's working out.

 

[BCP]

Using 155s out of shorter barrels was a fad on here for quite awhile.

I like shooting 150fmj out of my AR10. Way less recoil than 175s, cost half as much, still accurate enough for steel and rocks out in the desert.

The 169s were my favorite but I'm not paying 50cents each for them.

 

[MikeMiller]

10-4. I'm stuck with about 5# of the IMR variant so I'm on the hunt for some of the sierra 2155's.

I may have a few hundred if you really need some

 

[MikeMiller]

Using 155s out of shorter barrels was a fad on here for quite awhile.

I like shooting 150fmj out of my AR10. Way less recoil than 175s, cost half as much, still accurate enough for steel and rocks out in the desert.

The 169s were my favorite but I'm not paying 50cents each for them.

It was a 308 answer to the 260 back in the day before we had great laser range finders. Fall angle is better on a fast 155 than a 175-185. Plus it’s easier on semi auto action. Especially the M14 type

With that said I prefer the 175 in my semi autos these days.

 

[stello1001]

I shoot with an old school guy who runs 155s in our monthly belly match. We shoot out to 1000 yards and he does fairly well. He shoots them in a bolt gun and runs very long barrels but they should still work good in your AR.

I asked him yesterday specifically about which projectile and he uses the 155 smk.

I bought 200 of the 155 TMKs to try but have not yet loaded them.

 

[Scarface26]

I wouldn't say you are "stuck" with the IMR 4895... It does have some temperature sensitivity but is forgiving to load with wide nodes, is not "peaky," and generates good velocity.

Exactly.

 

[Scarface26]

It was a 308 answer to the 260 back in the day before we had great laser range finders. Fall angle is better on a fast 155 than a 175-185. Plus it’s easier on semi auto action. Especially the M14 type

With that said I prefer the 175 in my semi autos these days.

Do you prefer the 175's even over the 6.5CM? Or just over the 155's?

 

[MikeMiller]

No the 6.5 whips the 308 real good. If I did not have enough barrels, bullets and cases for a small war in 308 I would change to 6.5. Creedmoor for long distance.

Out to 600 yards you won’t see much advantage to 6.5 but afterwards the 308 requires a more precise wind call

 

[Ape_Factory]

I've always run IMR 4046 with 150's and have had good results. Never even considered 4895 for no real reason other than I've never looked at the stuff. What would be the advantages over 4046 out of a 16" barrel.

 

[MikeMiller]

I've always run IMR 4046 with 150's and have had good results. Never even considered 4895 for no real reason other than I've never looked at the stuff. What would be the advantages over 4046 out of a 16" barrel.

More speed from H4895. Less temp insensitivity than 4064