Sierra .30 CALIBER/7.62MM 169 GR. HPBT MATCH

[243Mendoza]

According to my CED M2 chronograph, about 2650. I mistranscribed the load in my post, which was actually 44.6 gn of Precision. I backed off from 45 gns because primers were cratering. Vels were 2610 @ 44 gns and 2670 at 45 gns.

According to Shooting Lab, the vel should be 1307 @1000. Quick Target is giving me 1257.

One of my problems is that I only have 150 of these bullets left and no one has them in stock. If I use 50 experimenting, I'll only have enough left to shoot one match.

I'm thinking of trying a load using 748, which (of the powders in my inventory) seems to give the best velocity within pressure limits.

I think that 1257fps (M=1.12) is too low for the Shotmarker to detect reliably.

 

[karrarararararar]

I figured a G7 of .2627 for them back in the fall. At 2650fps Strelok has you 1295 fps at 1000 yards.

 

[DRNewcomb]

Most likely too slow. I pushed them at 2875 out of a 32" to get ~1400fps on target at 1000. 1300 is getting into the territory that shotmarker won't register

Agreed. This is why I plan to try 748, which while not the best powder is one that should give the needed umpf within pressure limits.

One other issue is that ShotMarker was reporting velocities around 1600 fps at 600 yds. This is about 150 fps less that what Shooting Lab predicts. Now, in discussions with other shooters on the range, they say that the Shot Marker generally reports velocities lower that what is predicted. In any case, you can't use it for anything except shot-to-shot comparisons.

 

[Straightshooter1]

Does anyone have a BC table (BC vs vel) for the 169s rather than just the single (.527) value given by Sierra?

I tested some loads at 1000 on Saturday and found that while I could hit the metal gong at 1000 and hit a specific patch of dirt on the berm, I couldn't get the shots to register on the ShotMarker system. (I was loading 43.6 gn of Precision Rifle in a Lapua Palma .308 case shooting from a 26" barrel.)

Need to know what you're Density Altitude is, as that's a big factor.

The load I've been running recently for these 169's is giving me an average MV at 2767 fps and at an Density Altitude of 125 ft. my Strelok Pro gives me a velocity at 1000 yds of 1279.4 fps. When I change the DA to 4000 ft. It shows a velocity of 1404.8 fps at 1000 yds.

 

[DRNewcomb]

Need to know what you're Density Altitude is, as that's a big factor.

'Bout as close to sea level as you can get and have dry feet.

 

[Straightshooter1]

'Bout as close to sea level as you can get and have dry feet.

Hmmmm??? Well, that may not be much help as the DA can be very different from altitude above sea-level. For example, as you can see in what I posted above, the DA is at 125 ft., but the altitude above sea-level is at 880 ft. The DA is based on barometric pressure and humidity.

I have a feeling that Quick Target number of 1257 is probably close to the number you can expect with your load. ¯\_(ツ)_/¯

 

[DRNewcomb]

Hmmmm??? Well, that may not be much help as the DA can be very different from altitude above sea-level. For example, as you can see in what I posted above, the DA is at 125 ft., but the altitude above sea-level is at 880 ft. The DA is based on barometric pressure and humidity.
/¯

I plugged my current conditions into the NWS Density Altitude calculator and got 2254.2 ft. Since I don't understand the distinction, I can't comment on the accuracy of the answer.
At the range on Saturday, it was close to 1597.5 ft because it was 10º cooler.

 

[Monte F]

My shotmaker velocity was 1409-1416 fps for three strings at 1000 yds Sunday. Our range is at 4100 ft. the temps were low 50s to high 60s. I am not of sure of my muzzle velocity, need to review my Magneto Speed logs. I am loading 43.3 grns of Varget in large primer Starline brass out of a 30 inch barrel. No trouble picking up the shots at that speed.

 

[DRNewcomb]

My shotmaker velocity was 1409-1416 fps for three strings at 1000 yds Sunday. Our range is at 4100 ft. the temps were low 50s to high 60s. I am not of sure of my muzzle velocity, need to review my Magneto Speed logs. I am loading 43.3 grns of Varget in large primer Starline brass out of a 30 inch barrel. No trouble picking up the shots at that speed.

I ran this load in QL and came up with 2679 fps. Then I ran the ballistics at 4100 ft, 40% humid & 50ºF and it was predicted right at 1400 fps @ 1000 yds. I then changed the atmos data to 10 ft, 80 % and 70ºF and the 1000 yd velocity dropped to below 1200 fps. What a difference the atmosphere makes.

 

[Straightshooter1]

I ran this load in QL and came up with 2679 fps. Then I ran the ballistics at 4100 ft, 40% humid & 50ºF and it was predicted right at 1400 fps @ 1000 yds. I then changed the atmos data to 10 ft, 80 % and 70ºF and the 1000 yd velocity dropped to below 1200 fps. What a difference the atmosphere makes.

BTW: To give you and idea of the difference in Density Altitude and actual altitude above sea level, the altitude at my range is at 880 ft., but the conditions given the temperature and humidity, the DA calculates to 210 ft.

Yes, indeed . . . atmospherics like Density Altitude makes a big difference, especially at distance :

 

[6BRA]

I don't mean to sound pessimistic, but to believe that a 169 is waaaay better than a 168 makes my eyes want to roll.

Did you read the redesign?

 

[Straightshooter1]

Well, out having a little fun this windy dry morning :

 

[otnot]

The 169 fly's great but I can't get it to group well. I've tried 4 different powders(varget, imr4895, imr4064 and staball. I've tried seating depths from jammed to .100 out. I have shot 500 of them testing every variation I can think of. The only thing I can think of is that they don't like a 1:10 twist. I guess I will have to try my old Remington 700P with a 1:12 twist next.

 

[Straightshooter1]

The 169 fly's great but I can't get it to group well. I've tried 4 different powders(varget, imr4895, imr4064 and staball. I've tried seating depths from jammed to .100 out. I have shot 500 of them testing every variation I can think of. The only thing I can think of is that they don't like a 1:10 twist. I guess I will have to try my old Remington 700P with a 1:12 twist next.

My .308 RPR has a 1:10 Krieger 26" heavy barrel with 900 rounds through it. Before this barrel I had a 1:10 Krieger 24" Sporter and the 169's did well enough for me with H4895 and IMR-4064 getting groups in the .3's.

 

[DRNewcomb]

BTW: To give you and idea of the difference in Density Altitude and actual altitude above sea level, the altitude at my range is at 880 ft., but the conditions given the temperature and humidity, the DA calculates to 210 ft.

Yes, indeed . . . atmospherics like Density Altitude makes a big difference, especially at distance :

I'll try to be more aware of Density Altitude when shooting but since none of my ballistics programs have it or degrees Rankine as inputs, I think it's not so bad that that I wasn't using it.

 

[DocCarbon]

What I'd like to see is a BC of .520 out of MY 173-74 Gr. Military Match pills ,with a total redesigned bullet .

I've got 10's of K's of those .

 

[otnot]

My .308 RPR has a 1:10 Krieger 26" heavy barrel with 900 rounds through it. Before this barrel I had a 1:10 Krieger 24" Sporter and the 169's did well enough for me with H4895 and IMR-4064 getting groups in the .3's.

Well I guess it's back to the drawing board then. hopefully I can find the right elixir with the 1,000 remaining bullets. LOL

 

[Packrat1947]

The Sierra 169 came out in 1958 for 300 meter Olympic shooting. The AMU used them.

 

[GotRDid]

Typo: 168 gr.
Old thread, but I’m working up some loads with VV140 I was gifted; host is a Ruger M77 with 1/10 twist 25” Douglas SS bbl.
I’ve shot a boat load of M852 through our Team’s M14s (yes M14NM) until I bought my own M1A NM way back when. The M852s were a lot more consistent than the M118 we started out with. The M118LR has been very consistent as well for mass produced ammo.