Sierra 190 SMk v. 175

[bamaranger]

All things equal, does the added .29 edge the .30 caliber 190 gr Sierra Match King has over the 175 SMK pose a real advantage (.525 v. .496) in slipping the wind at 500 and 600 yds? Can I "buy" a few points in F-T/R, if my rifle shoots 175's and 190's with equal accuracy. Put another way, if I miss a wind call, can a 190 turn an "8" into a "9", or a 9 into a 10. I don't even think about shooting "x's" in the wind!

Yeah, I know, shoot more and learn the wind. But can a heavier slug gain me anything over mid range courses???

At 1000 yds, I'm not sure the velocity is sufficient, but at 300, 500-600, it seems lots of my competitors are shooting 190's.

Finally, if there is an edge, and one decides to shoot 190's, when I rebarrel from my Savage factory heavy barrel (1-10?) should I change twist? Seems like most of the 190 shooters are also using custom barrels. Have they upped the twist rate to accommodate 190's ?

[4EVERM-14]

A good friend shot 190's in a bolt gun while I shot 168's from a service rifle at 600yds.{XTC} He being a better shot I expected a bigger difference between our scores. The results did not show that. I suspect that the 190 cannot be driven fast enough from a .308 to benefit from the extra mass. The larger capacity of the 30-06 perhaps could.
I was always a believer in mass over velocity but with the VLD type bullets speed might have the advantage. Of course this all goes out the window if you point at the 8 ring and pull the trigger,like I do.

[5RWill]

If you want you could look at a 175gr with a better BC than the SMK. The berger 175gr BR LR has a G1 BC of .515 and a G7 BC of .264 putting it alot closer to the 190 SMK in terms of BC. You'll still have less wind drift with the 190 SMK. I think it's more of a personal choice, due to it being 600yds. They both work well. If it were 1000yds i would opt for the 175gr because the likely hood of pushing a 175gr bullet around 2650+ is pretty good. I agree with whats stated above also, the velocity of a .308 pushing a 190gr SMK just doesn't seem good enough to reap the benefits of the higher BC.

[Michael]

Having shot few 10,000's of 175's over the years, and then
switching to 190's;
The 190's will give less drift per distance than the 175's
The 175 is a squirrely bullet if you drive it fast in the wind, while the 190 is like a freightliner; it moves predictably and it takes a lot of influence to move it.
The 190's will deliver more energy on knock down type targets than the
175's, disproportionate to their weight advantage.
190's fired at 2600fps will out perform 175's fired at 2700fps.

I quit shooting 175's in my bolt rifle and use them only in my M1A.
I've shot 190's for 6 years and see no reason to return to 175's for target shooting.

[5RWill]

At 600yds they are about equal in ballistics using the FPS above ^.

175SMK @ 2700fps @ 600yds

Drop(mil) Windage(mil)
4.4 1.4

190SMK @ 2600fps @ 600yds

Drop(mil) Windage(mil)
4.6 1.3

That being said the berger 175gr BT LR best them both IMO.

[Slamfire]

All things equal, does the added .29 edge the .30 caliber 190 gr Sierra Match King has over the 175 SMK pose a real advantage (.525 v. .496) in slipping the wind at 500 and 600 yds? Can I "buy" a few points in F-T/R, if my rifle shoots 175's and 190's with equal accuracy. Put another way, if I miss a wind call, can a 190 turn an "8" into a "9", or a 9 into a 10. I don't even think about shooting "x's" in the wind!

I have shot both at 600 and 1000 yards. Both are very accurate bullets. The 190 was the most common 600 yard bullet in the 70’s in the 308, from a survey taken at Camp Perry. It does kick more and you really have to push it at maximum pressures to get 2500 fps or better. I have never received 2600 fps with 190’s in my rifles. Primers get blown before I reach that velocity. I am happy with 2550 fps.

Having shot both, you miss your wind call, you are hosed. 155, 175, 190. There is no salvation for a wind change in 308. Your score is on an elevator ride down, down, down. :mad:

So, find what shoots best and use that.

If you want you could look at a 175gr with a better BC than the SMK. The berger 175gr BR LR has a G1 BC of .515 and a G7 BC of .264 putting it alot closer to the 190 SMK in terms of BC. You'll still have less wind drift with the 190 SMK

This reminds me of the 50’s-60’s Wildcat days when wildcatters were promoting the warp speed of their cartridges. No one had chronographs back then so the numbers were unverifiable, but the makers sure made sales based on their numbers.

Sierra is always very conservative in calculating their BC's. Sure other manufacturer's put out high BC numbers but there is no one out there verifying the validity of these numbers, and high numbers mean increased sales, and they are all in it for the profits. So, should you trust big numbers from someone with a financial incentive to make them big? :confused:

In my opinion, between bullets of same caliber and weight, you should only trust what you see on paper. If it shoots good it is good. ;)

[5RWill]

Brian litz has verified the BC of the berger BT LR in applied ballistics which is G1 of .515 and a G7 of .264. Contrary to what most people think the 155gr scenar doesn't have a G1 BC of .508. It has a G1 of .460 and a G7 of .230 from lapuas website and G7 of .238 according to litz, so it differs a little.

That being said I do agree actual data out in the field is more valuable and reliable than a calculator. But the calculator does help you to get there

[kraigwy]

You are asking the wrong place. You should be asking this question of your gun.

All guns are differant, only the individual gun can answer correctly.

Example. I have a Model 70 Winchester set up for 1000 yard shooting. Its a Douglas prem. Match barrel with in 1:10 twist. It dosen't like 190s or 175 SMKs but loves the 200 grain SMK.

I also have a Model 70 in 30-06, same barrel, a bit shorter (26 Vs 29). It likes the 175s over both the 190s and 200s.

Then comes my M1 Garand. It likes the old military 174 grn match bullet better then any of the above.

My Super Match likes the 168 SMK but in 1000 yard matches 168s don't work so it makes do with the 175 SMKs. It like the old SMK 180s best of all but they arn't the same as todays version of the 180 SMKs.

Go Figure.

[Jimro]

Depending on the bullet to make the difference between a 9 and an X seems like a bad plan to me. I know a few guys that were pushing 190's out of a 308 for a while, couldn't get above about 2,450 fps without pressure signs. However in a 30-06 it is a different story. And in a 300 Win Mag the 190 is a no brainer (although the 175 will normally shoot great from either as well).

Jimro

[5RWill]

Well I agree, the reason I lean toward high BCs is just because I want the least amount of elevation I can get, along with the most energy retained down range I can get. Anything to help me be quicker in a sense. Of course I'm thinking in the sense of practical LR shooting not F-class.

[csmsss]

I'd say that the 175 is really the top end for .308. Loading the 190's into that case is just too problematic for my liking.

[Buzzcook]

Depends on the gun and the cartridge.

I agree with csmsss I'd be hesitant about putting anything heavier than 175gr in a .308.

1-10 seems to be standard with .30 caliber rifles. Not sure how much help a faster twist would be for heavier bullets.
I'd guess increasing barrel length and or moving to a more powerful cartridge would help heavier bullets more than a faster twist.

[Jimro]

1:10 is fine for everything but the really heavy 240gr pills launched subsonic, but if you are loading a 300 Whisper you should really know that already.

You can load 168 and 175 match bullets subsonic in a 1:10 barrel just fine.

Jimro

[HAMMER1DOWN]

Old topic but I wanted to ask. Yesterday at the range I was able to push my 190's to 2701 avg with 44.4 grains Varget, LC 12 brass, BR-2 primers. Nothing to show pressure over flattened primers, no cratering to speak of. My question is can the .308 be driven to 2800 FPS without frying my barrel?

[Bart B.]

I think 190's leaving a .308 Win barrel over 2700 fps have at least one of two things going for them:

* The muzzle's at least 32 inches away from the bolt face.

* Peak pressure's way, way too high for safety and reasonable accuracy.

Someone with Quickload should check this load out after HAMMER1DOWN posts his barrel length and his approximate case capacity.

A popular load with 190's in the .308's with 26 inch barrels and thin wall, WCC58 match cases (case weight is only 150 grains) was 42 grains of IMR4064. It produced muzzle velocities about 2600 fps at pressures at the upper SAAMI spec limit.

[HAMMER1DOWN]

26" barrel with 1/12 twist, seated at 2.860. Load produced just under an inch at 200yds. I'm sure pressure is through the roof. But mic'd the fired cases comparred to unfired cases and only place where brass was over .001-.002 was at the neck. Even there it was only .006 over unfired case, outside diameter.