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working up a load for Mr Roberts #16497154 10/04/21
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southtexas Offline OP
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Respectfully submitted to the Campfire brain trust:


115gr Nosler PTs that were recently on sale at SPS
H100V based on jwall's recommendations

Tried loading 11 rounds, increasing 1/2 grain at a time and measuring the MV

Results:

42gr 2904 fps
42.5 2923
43 2982
43.5 2989
44 3030
44.5 3072
45 3100
45.5 3108
46 3152

stopped there as the bolt lift was getting stiff.

What do these data say to you with respect to where I should look for a node? TIA

BP-B2

Re: working up a load for Mr Roberts [Re: southtexas] #16497179 10/04/21
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While Hodgdon does list 46gr as the max with that bullet and R-P brass, they got 100fps than you in their 24" test barrel. What barrel length do you have? I'd not push it beyond what you're supposed to be seeing, regarding velocity. Going much above that can only come at the expense of pressure.


Now with even more aplomb
Re: working up a load for Mr Roberts [Re: southtexas] #16497189 10/04/21
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southtexas Offline OP
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JPro

M70 FWT XTR, 22" bbl

Re: working up a load for Mr Roberts [Re: southtexas] #16497214 10/04/21
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Gotcha. I'd knock off about 25fps an inch and expect 3,000fps to be a reasonable ceiling if H got 3,050 with their 24" tube. If it were me, I'd load about 43.7 and see what I could do for accuracy with a couple of different overall lengths. If you're shooting it in TX recently, then you're probably dealing with reasonably warm weather, so you should be good for pressure even if hunt temps get up to 85 or so. I'd try to shoot for accuracy on a cool morning with no wind.


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Re: working up a load for Mr Roberts [Re: southtexas] #16497438 10/04/21
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Dirtfarmer Online Content
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Don't forget about the 100 TTSX. Agree that H-100V is a velocity champ in the Roberts. This load really whacks hogs and WT's. BTW, note COAL for the LA, a bit much for a SA.

Slightly more accurate in my gun (24" Brux barrel, Rem 700) was the 115 NBT over H-4350, although not as fast, more like 2,950 or so, it whacks'em, too.

DF

[Linked Image from i.imgur.com]




Last edited by Dirtfarmer; 10/04/21.
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Re: working up a load for Mr Roberts [Re: southtexas] #16498362 10/04/21
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beretzs Offline
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Originally Posted by southtexas
Respectfully submitted to the Campfire brain trust:


115gr Nosler PTs that were recently on sale at SPS
H100V based on jwall's recommendations

Tried loading 11 rounds, increasing 1/2 grain at a time and measuring the MV

Results:

42gr 2904 fps
42.5 2923
43 2982
43.5 2989
44 3030
44.5 3072
45 3100
45.5 3108
46 3152

stopped there as the bolt lift was getting stiff.

What do these data say to you with respect to where I should look for a node? TIA



45 looks like where I’d try working with your data.


Semper Fi
Re: working up a load for Mr Roberts [Re: beretzs] #16498431 10/04/21
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bsa1917hunter Offline
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Originally Posted by beretzs
Originally Posted by southtexas
Respectfully submitted to the Campfire brain trust:


115gr Nosler PTs that were recently on sale at SPS
H100V based on jwall's recommendations

Tried loading 11 rounds, increasing 1/2 grain at a time and measuring the MV

Results:

42gr 2904 fps
42.5 2923
43 2982
43.5 2989
44 3030
44.5 3072
45 3100
45.5 3108
46 3152

stopped there as the bolt lift was getting stiff.

What do these data say to you with respect to where I should look for a node? TIA



45 looks like where I’d try working with your data.

I'd shoot some groups and see what the rifle likes. If he's getting stiff bolt lift, that means it is about a grain too many. Maybe even more. Likely to be safe, a grain and a half. Where I'd start is 43, then work up from there. Not exceeding 44.5 grains. Find an accuracy node and OCW, then if need be, adjust oal. Also, regarding the partition: I'd run them at .020" off the lands and expect to find a good load in between 43-44.5 gr charge weights. If he's not, switch powders. H4350 or IMR4350 would be sure bets in the accuracy department.


Originally Posted by raybass
I try to stick with the basics, they do so well. Nothing fancy mind you, just plain jane will get it done with style.

Originally Posted by Pharmseller
You want to see an animal drop right now? Shoot him in the ear hole.
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Re: working up a load for Mr Roberts [Re: southtexas] #16498529 10/04/21
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Yeah, for sure. I was just looking at the OCW numbers he posted. Hard to tell what stiff bolt lift means. I look for a plateau where adding more doesn’t do much if anything to speed. Tends to work out to lower ES loads in my experience.

Always hard to judge others work and feel what they’re feeling.


Semper Fi
Re: working up a load for Mr Roberts [Re: southtexas] #16498940 10/04/21
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My .257 Roberts shot better with those SPS 115 partitions with the stubby ogive than any other bullet I ever fed it. I posted about it a while back. I used Ramshot Magnum and it went consistently sub MOA. Never did that well before. After a bunch of trials I settled on 50.8 gr at 3000 FPS.
Here's the thread where I wrote about it. There is some earlier work-up posts if you scroll up but the bottom-line, end results are here:
Good .257 155 stubby partition load

Cheers,
Rex

Re: working up a load for Mr Roberts [Re: beretzs] #16499024 10/04/21
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bsa1917hunter Offline
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Originally Posted by beretzs
Yeah, for sure. I was just looking at the OCW numbers he posted. Hard to tell what stiff bolt lift means. I look for a plateau where adding more doesn’t do much if anything to speed. Tends to work out to lower ES loads in my experience.

Always hard to judge others work and feel what they’re feeling.

Its smart to look for that plateau Scotty. You've been loading accurate ammo for a long time. I remember seeing your posts on the Nosler forums before here. I'm sure the OP appreciates your input..


Originally Posted by raybass
I try to stick with the basics, they do so well. Nothing fancy mind you, just plain jane will get it done with style.

Originally Posted by Pharmseller
You want to see an animal drop right now? Shoot him in the ear hole.
P


BSA
IC-B

Re: working up a load for Mr Roberts [Re: southtexas] #16504984 10/06/21
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southtexas Offline OP
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Thanks much for the inpu, Gentlemen. I appreciate you sharing your expertise. Think I will nibble around, 43 and 43.5, the bolt lift at 46 was pretty stiff and 3150 seems likke a pretty optimistic MV for a Roberts.
Tried earlier with 43gr of IMR4350 with different OALs. None were particularly good but 2.75" was the best.. So perhaps 43gr and 45.5gr at that OAL.

115gr PTs at just under 3000fps sounds like a real sweet spot for my needs.

Thanks again (wish I had some Ramshot Magnum!

Re: working up a load for Mr Roberts [Re: southtexas] #16505476 10/07/21
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michiganroadkill Offline
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The 3 different Bobs I have owned all preferred 100 grainers over heavier bullets.
So 100 NPs get to go hunting this year.
I did use a 100 BT a couple years back with success.


"The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
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Re: working up a load for Mr Roberts [Re: southtexas] #16508702 10/08/21
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Originally Posted by southtexas
Thanks much for the inpu, Gentlemen. I appreciate you sharing your expertise. Think I will nibble around, 43 and 43.5, the bolt lift at 46 was pretty stiff and 3150 seems likke a pretty optimistic MV for a Roberts.
Tried earlier with 43gr of IMR4350 with different OALs. None were particularly good but 2.75" was the best.. So perhaps 43gr and 45.5gr at that OAL.

115gr PTs at just under 3000fps sounds like a real sweet spot for my needs.

Thanks again (wish I had some Ramshot Magnum!


Glad to see you chose the 43/43.5 gr range. I would have done the same. I'd go out and shoot 3-shot groups of 43, 43.2, 43.4 and see which gives you the smallest ES/SD. Don't even need to shoot on paper, rather paying attention to the lowest ES/SD. Pick the smallest and then go test COAL. I'd start .005" to .010" off the lands and shoot 3-shot groups in .025" increments off the lands. Velocities will be similar but will decrease a small amount as you get further from the lands. Some where in there you should see a, or several, smaller group/s. I've killed elk with a Nosler 115 running in the 2890 range. Have confidence you 115 will do anything you ask of it.

Enjoy

Alan

Re: working up a load for Mr Roberts [Re: southtexas] #16511752 10/09/21
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Well, we can see why you are getting a stiff bolt:
I'd be comfortable loading the Feather weight up to about 65K PSI.

Code
Cartridge          : .257 Roberts +P+ (not SAAMI)
Bullet             : .257, 115, Nosler BalTip 25115
Useable Case Capaci: 47.495 grain H2O = 3.084 cm³
Cartridge O.A.L. L6: 2.775 inch = 70.49 mm
Barrel Length      : 22.0 inch = 558.8 mm
Powder             : Hodgdon Hybrid 100V

Predicted data by increasing and decreasing the given charge,
incremented in steps of 1.136% 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

-11.4   92    39.00   2631    1767   41497   9895     98.7    1.277
-10.2   93    39.50   2663    1811   43115   9994     99.0    1.254
-09.1   94    40.00   2696    1856   44790  10086     99.3    1.232
-08.0   96    40.50   2728    1900   46532  10172     99.5    1.211
-06.8   97    41.00   2760    1946   48350  10251     99.7    1.190
-05.7   98    41.50   2792    1991   50242  10324     99.8    1.170  ! Near Maximum !
-04.5   99    42.00   2824    2037   52211  10390     99.9    1.150  ! Near Maximum !
-03.4  100    42.50   2856    2083   54252  10448    100.0    1.130  ! Near Maximum !
-02.3  102    43.00   2888    2129   56366  10499    100.0    1.111  ! Near Maximum !
-01.1  103    43.50   2919    2176   58562  10547    100.0    1.092  !DANGEROUS LOAD-DO NOT USE!
+00.0  104    44.00   2950    2223   60846  10592    100.0    1.074  !DANGEROUS LOAD-DO NOT USE!
+01.1  105    44.50   2982    2270   63222  10637    100.0    1.056  !DANGEROUS LOAD-DO NOT USE!
+02.3  106    45.00   3013    2317   65695  10681    100.0    1.038  !DANGEROUS LOAD-DO NOT USE!
+03.4  107    45.50   3043    2365   68270  10723    100.0    1.021  !DANGEROUS LOAD-DO NOT USE!
+04.5  109    46.00   3074    2413   70952  10764    100.0    1.004  !DANGEROUS LOAD-DO NOT USE!
+05.7  110    46.50   3105    2461   73747  10804    100.0    0.988  !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 3% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 3% relative to nominal value:
+Ba    104    44.00   2987    2278   64602  10448    100.0    1.049  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 3% relative to nominal value:
-Ba    104    44.00   2909    2161   57092  10747     99.9    1.102  ! Near Maximum !

Last edited by antelope_sniper; 10/09/21.

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Re: working up a load for Mr Roberts [Re: southtexas] #16523555 10/13/21
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My 257 Roberts model 70 shoots the 115gr nosler partitions better than any other bullet. The load that came with the used rifle was 43.5gr of IMR 4350 at about 2925 FPS killed half dozen Antelopes with

That load. I got 3130 FPS using RL26, RL23 with 110gr Accubonds gave 3120 with 7.8 SD Win cases, CCI250 Primers OAL was 2.840. RL23 with 115gr Nosler Partitions and CCI primers R/P case

got 3129 FPS SD was 14.5. I also used MRP with the 115gr Bullets it has about the same speed as the RL23, don,t have it in front of me right now. I highly recommend the 115gr Nosler Partitions.


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