7mag & 150 CTBT's, first shots.

[Darkhorse]

This was my first range session since my total knee replacement and I didn't shoot so well. This was also my first session with the CTBT bullet.
My barrel was squeaky clean and the first 3 fouling shots from a cold barrel were the best group. This was a surprise even though the load is the most accurate I've found with the regular BT's, these were only intended as fouling shots. All groups impacted very near the same POI.
I'm looking for an accurate load at 63. grains of IMR 4350 for hunting. And so far the CBT's are shooting better than the regular Ballistic Tips at this load. The bullet seems to want more jump so the next set will all see a deeper seat depth.
On group A, I pulled the last shot, it is the one to the left, out of the group. On group B, I also pulled the last shot it is low to the right. Group C felt good and I will shoot it again.
I will also increase the size of the red circles to match the one on the single target as I could see it much better in the scope.
All the groups hit right and low of the regular Ballistic Tips and were generally more accurate, even with the shooter errors.
Since these are the first shots with a clean barrel I don't know what to expect from this coated bullet, perhaps the groups will tighten with more shots down the barrel.

 

[JD338]

I'd try seating out to .40" and .045" and see what happens.

JD338

 

[Alderman]

I'm tickled if I get a group like this. I would think hunting with this would be a pleasant event.

 

[Ridgerunner665]

If it were me...I'd put some more rounds through it before I made any decisions...

What I see...is the groups tightening back up as the round count goes up...most rifles will settle down after a deep cleaning within 20 rounds....some take more, some less...but I would fire some more rounds (without deep cleaning the barrel...lube only).

About the size of the circles...the old saying "aim small, miss small"...that saying is 100% true.

A lot depends on the reticle in your scope (thinner is better, up to a point)...but the smaller the bullseye the better for accuracy testing...maybe change the color to make it more visible for you, but I'd leave the size as small as possible.

 

[Dwh7271]

DH,
Nice shooting.
Got to love a 7 mag.
Great cartridge.

 

[DrMike]

I've had good success with the Combined Technology line of bullets in both my .280 and 7mm RM. You appear to have a pretty good load there. I would think some additional work with that load will bring a grin to your chin each time you pull the trigger.

 

[wisconsinteacher]

You just made up my mind, I will be trying IRM4350 in my 7mm RM. Great shooting.

 

[Darkhorse]

About the size of the circles...the old saying "aim small, miss small"...that saying is 100% true.

Most of the time I'd agree but with only a 10X scope I've found I need a large enough circle that I can see it well enough to see all 4 quadrants equally along with no daylight between the crosshairs and the lines on the target. I've been experimenting with this and I could see the slightly larger circle on the single target really well.
Of course the better answer is a higher powered scope and that will be my next scope purchase when I get the funds.
My next set will be seated at .035 (reshoot), .040 and .045.
I picked the seating depths as a continuation of a string fired with the regular BT's. Looking at my other targets it's clear how accuracy changes as the barrel ocilates. When the node is reached the gun shoots sub .200 with 60.5 or 61. grains. It was with 62. and 63. grains that I was having problems with. And since long shots are expected on the powerline I just felt I needed a hotter load.
The CTBT bullet seems to be less fussy than the regular BT's in my rifle. At least so far.
I don't plan on cleaning the bore anytime soon, I want to see how she shoots with a few more rounds down the barrel.
If I had shot all 12 rounds on the same bull then you couldn't have known which were fouling shots and which were for record. I can't say the same for some other rifles and bullet combo's.
This is the target shot previously with 63. grs. and regular BT's.

 

[OU812]

I'm tickled if I get a group like this. I would think hunting with this would be a pleasant event.

I'm right with ya. All I know is the 60.5 load @.388 would be my partner at the dance. That's good shooting.

 

[Darkhorse]

I hear you Alderman and OU812, but using the regular Nosler Ballistic Tip 150's I've gotten slightly better groups. 3 shots at .181 60.5 IMR 4350, 3 shots at .221 opening up to .666 with 5 shots, 61. IMR 4350. All of these have been posted here.
So I think it's well worth shooting a few more loads at 63. grains just to see how it all pans out.
After that I'll make a decision. But yeah, there are several loads I'd be comfortable hunting with in this bunch.

 

[OU812]

If one can scoot them along a little faster and only open up to about 1/2 MOA why not. Lots of great hunting load choices.

 

[Darkhorse]

If I can get .5 regularly at 63. grains I think I'll be happy.

 

[OU812]

I can see where .5 MOA @ 63 grains on a regular basis would make a guy happy. Let hope you get it.

 

[SJB358]

Great shooting! What a great load. Hope the higher charge works out for you.

 

[Jgraider]

Long time reader and lurker here, first time poster. Looks like you're really onto something there Darkhorse. What velocity are you getting with those loads?

I've been loading for and hunting with a 7mag for almost 40 years. I didn't like the first generation BT's, but the CTBT's I've tried have been very accurate, and work great on big mule deer bucks. They are much tougher nowadays.

Good luck with your load work up Darkhorse...please keep us posted.

 

[DrMike]

Long time reader and lurker here, first time poster. Looks like you're really onto something there Darkhorse. What velocity are you getting with those loads?

I've been loading for and hunting with a 7mag for almost 40 years. I didn't like the first generation BT's, but the CTBT's I've tried have been very accurate, and work great on big mule deer bucks. They are much tougher nowadays.

Good luck with your load work up Darkhorse...please keep us posted.

Welcome aboard, Jgraider. Always good to see new folk posting. I discover that many of those posting for the first time have a wealth of experience. Here you'll find a good group ready to mine the depths of your knowledge.

 

[Darkhorse]

Long time reader and lurker here, first time poster. Looks like you're really onto something there Darkhorse. What velocity are you getting with those loads?

/quote]

Can't say for sure since my chrono died a few years back. If I can find a load I like at 63 grs. of IMR 4350, max in the Nosler books, I'm going to just figure it at 3,000 fps. I don't think it will go the published 3200. I'll be hunting a powerline with the 7mag and the max distance is about 420 yards.
There is a good trail crossing right at the 420 mark and a good one at 351, then a couple more closer in. I have built a shooting house so I'll have a solid rest for those long shots. And the distances are marked simplifying holdover.
A new chrono is on the list, but it will come after a new scope.

 

[SJB358]

If you weigh out five of your cases (average) then fill them with H20 to get the average weight, then do a little subtraction we could run your load in QL and I imagine we'd get fairly close, at least to within 100FPS I bet.

Cartridge : 7 mm Rem. Mag.(SAAMI)
Bullet : .284, 150, Nosler CT BalSilTip 51110
Useable Case Capaci: 74.094 grain H2O = 4.811 cm³
Cartridge O.A.L. L6: 3.290 inch = 83.57 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : IMR 4350

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 74 50.40 2477 2043 34071 9775 94.0 1.515
-18.0 76 51.66 2533 2137 36175 10049 95.0 1.480
-16.0 78 52.92 2589 2232 38397 10314 95.8 1.441
-14.0 80 54.18 2645 2330 40742 10566 96.6 1.400
-12.0 82 55.44 2700 2429 43216 10807 97.3 1.361
-10.0 83 56.70 2756 2529 45828 11036 98.0 1.323
-08.0 85 57.96 2810 2631 48585 11250 98.5 1.287
-06.0 87 59.22 2865 2734 51495 11450 99.0 1.253
-04.0 89 60.48 2919 2838 54568 11634 99.3 1.219
-02.0 91 61.74 2973 2944 57813 11802 99.6 1.187 ! Near Maximum !
+00.0 93 63.00 3026 3051 61241 11954 99.8 1.156 ! Near Maximum !
+02.0 95 64.26 3079 3158 64864 12088 100.0 1.126 !DANGEROUS LOAD-DO NOT USE!
+04.0 96 65.52 3132 3267 68695 12205 100.0 1.097 !DANGEROUS LOAD-DO NOT USE!
+06.0 98 66.78 3184 3376 72747 12312 100.0 1.069 !DANGEROUS LOAD-DO NOT USE!
+08.0 100 68.04 3235 3485 77038 12416 100.0 1.042 !DANGEROUS LOAD-DO NOT USE!
+10.0 102 69.30 3286 3596 81583 12517 100.0 1.017 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 93 63.00 3131 3264 71071 11576 100.0 1.082 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 93 63.00 2877 2756 51411 11937 96.6 1.252


This is what QL shows for a standard profile using 82.00 grains of H20 as the overall case capacity. I haven't seen a 7mm Rem Mag case fired in any rifle yet be smaller than 82 grains, most are in the 85-87 range. So you should be in the 2900-3000 range with 63 grains. Again, all depends on your barrel and such, but a decent idea to where your at.

 

[Darkhorse]

Try 85.2 grains of water.
And 3.390 OAL.

 

[SJB358]

Here is what it looks like.

Cartridge : 7 mm Rem. Mag.(SAAMI)
Bullet : .284, 150, Nosler CT BalSilTip 51110
Useable Case Capaci: 79.617 grain H2O = 5.169 cm³
Cartridge O.A.L. L6: 3.390 inch = 86.11 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : IMR 4350

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 73 53.20 2519 2114 34879 10370 95.0 1.508
-18.0 75 54.53 2576 2210 37016 10652 95.9 1.474
-16.0 77 55.86 2632 2308 39269 10923 96.7 1.432
-14.0 78 57.19 2688 2407 41643 11181 97.4 1.391
-12.0 80 58.52 2744 2507 44146 11425 98.0 1.352
-10.0 82 59.85 2799 2609 46782 11655 98.6 1.315
-08.0 84 61.18 2854 2713 49561 11871 99.0 1.280
-06.0 86 62.51 2908 2817 52489 12070 99.4 1.246
-04.0 87 63.84 2962 2923 55576 12252 99.7 1.213 ! Near Maximum !
-02.0 89 65.17 3016 3029 58830 12417 99.9 1.181 ! Near Maximum !
+00.0 91 66.50 3069 3137 62262 12563 100.0 1.151 ! Near Maximum !
+02.0 93 67.83 3121 3245 65882 12692 100.0 1.121 !DANGEROUS LOAD-DO NOT USE!
+04.0 95 69.16 3173 3354 69703 12813 100.0 1.093 !DANGEROUS LOAD-DO NOT USE!
+06.0 97 70.49 3225 3463 73737 12932 100.0 1.065 !DANGEROUS LOAD-DO NOT USE!
+08.0 98 71.82 3276 3574 78000 13047 100.0 1.039 !DANGEROUS LOAD-DO NOT USE!
+10.0 100 73.15 3326 3685 82506 13159 100.0 1.014 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 91 66.50 3169 3345 71986 12175 100.0 1.078 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 91 66.50 2923 2846 52468 12635 97.4 1.246