155g Nosler custom Comps

[StoneTower]

http://www.sierrabullets.com/bullets...ient-rifle.pdf
Sierra 155gr BC=0.450

http://www.nosler.com/index.php?p=11&b=5&s=4&t=30cal

Nosler 155gr BC=0.450

I've shot a couple hundred through my old 1:10" barrel and they did well. They also do well out of the 1:12" that I'm using now.

What kind of gun and what was the charge and COAL?

Thanks,

David

[30Cal]

M1A w/ Kreiger 1:12" heavy. I'll have to look up the charges, but I've used Varget & surplus 4895. They probably aren't all that meaningful though as I use GI brass and my chamber is very tight (I have to use an SB die and a SMK is against the lands at around 2.82" OAL)--I'm typically more than 1gr less than most people to get the same velocity.

[EBR Works]

I have a 2 month old DPMS upper with 24" 1:10 stainless heavy barrel on a POF lower. I have tried the same 155 gr Nosler bullet as follows:

Once fired CBC brass. All FL re-sized in a RCBS comp die and trimmed to 2.015 with a Possum Hollow trimmer then deburred, chamfered, primer pocket uniformed and flash hole deburred on an RCBS Trim Mate. CCI 200 primer used since I could not find CCI BR2s. Charges thrown from a RCBS Chargemasters Combo. Bullet seated with an RCBS comp die to a COL of 2.800 with no crimp.

I loaded Varget at 43, 44, 45, 46 and 47 gr with 44 gr giving the best 5 shot group at 100 yds of .714". The 47 gr load had similar results but was quite compressed.

I'm headed out tomorrow with a batch loaded at 44 gr and 46.5 gr with CCI BR2 primers to see if I can do better and see how they do at 200 yds.

[Jicko]

impacto, for the record, if possible, post your MV, and its ES and SD.

My past data showed that #200 and #BR2 are of similar MV, but the ES and SD are halved. Also, accuracy of the #BR2 is better (obviously... lol)

[EBR Works]

impacto, for the record, if possible, post your MV, and its ES and SD.

My past data showed that #200 and #BR2 are of similar MV, but the ES and SD are halved. Also, accuracy of the #BR2 is better (obviously... lol)

My next purchase will be a chrono after tax refund.

[EBR Works]

As a follow-up to my post above, I got out today to see if I could improve my groups with the NOS 155 projectiles. The winds were variable at about 15 knots. My best group at 100 yds was with 46.5 gr of Varget and the same brass prep as mentioned above.

.886"-.308"=.578"

I need a calm day and a better trigger than the RRA NM and I'm hopeful that I can get these groups into the .3xx range. We'll see.

[ar15barrels]

.886"-.308"=.578"

Measure a single bullet hole in the exact same piece of paper and you will find that the holes don't measure 0.308".
You need to know what a single hole measures in the exact paper before you can subtract it's diameter to come up with group size.

[EBR Works]

Ok. Measured hole size is .302 so that makes the group .584". Thanks for the tip!

[EBR Works]

I shot these through my new chrono today and here are the results:

Load: 155 NOS HPBT, 46.5g Varget, CBC brass, CCI BR2 primers. COL 2.800

Alpha Master chrono positioned 10' from the muzzle.

1: 2909
2: 2921
3: 2904
4: 2928
5: 2920
6: 2916
7: 2921
8: 2911
9: 2916
10: 2918

High Velocity: 2928
Low Velocity: 2904
Average Velocity: 2916
Extreme Spread: 23.90
Standard Deviation: 6.85

Elevation: 3300 MSL
Temp: 71 F
Wind: 10-15kt crosswind

Due to the wind, groups were no better than .610" at 100yds. I have to get to the range in the early morning sometime when it's calm!

[30Cal]

That seems pretty fast for only a 20" barrel. Near max?

[ar15barrels]

That seems pretty fast for only a 20" barrel. Near max?

No kidding.
He must have thick brass.

I run 46.5gr of Varget under Sierra 155 SMK's in Federal GMM brass and get 2840fps from a 24" barrel.

[EBR Works]

These numbers are from a 24" barrel. I would assume the higher velocity was due to the 3000' elevation at Ojai.

[ar15barrels]

These numbers are from a 24" barrel. I would assume the higher velocity was due to the 3000' elevation at Ojai.

Muzzle velocity does not change with elevation.
Bullet drop changes with air density.
Increased altitude usually gives you reduced air density.

[EBR Works]

Muzzle velocity does not change with elevation.
Bullet drop changes with air density.
Increased altitude usually gives you reduced air density.

Understood.

The load is near max with slight primer cratering but no primer flattening.

I also tried some 175 Sierra HPBT loads through the chrono and saw 2720fps average with 44gr of Varget. There was some primer cratering with all of these loads ranging from 42-44gr of Varget.

The same bullet fired during the same range session from my Garand with 49gr of IMR4895 and Winchester brass yielded a 2728fps average which is slower than I expected.

It must be the CBC brass.