260AI fire forming load

[Creedmore]

Just got word from my gunsmith that my daughter's 260AI will be ready next week. :grin: So, time to get working on some fire form loads to do barrel break-in.

I have a surplus of 120gr Ballistic Tips (also shoot them in my 6.5 Grendel) so this is what I'll use to form brass and possibly for youth season in Missouri in a few weeks if I run out of time to work up a 130 AB.

I'm looking for suggestions on 120gr fire form loads. As I said, this will be double-duty as I will be breaking in the barrel so I won't be using cream of wheat, etc. I have plenty of H4831 & RL22 on hand.

Thanks,
-Gene

 

[Creedmore]

I've found recommendations for 140gr bullets, using a max charge of .260 Remington published load. And this is basically the method I used when forming my .280AI brass - a max load of .280. So my tentative plan is to run a book max 50 gr H4831 for the 120gr bullet.

 

[gerry]

I have only worked with the standard 260 Rem but did have a great load in my previous gun of 48 gr H 4831sc and a 120 gr Rem CL bullet. I would think the same load with the 120 gr Ballistic Tip would be a good place to start. There are lots of great powders that will do well, my new 260 Rem really likes H 4350 in particular.

 

[SJB358]

Very cool, I would say a full load of H4831 would get some nice looking cases plus you should be able to break that barrel in some. I bet it is going to be a tack driver! Pictures whenever you can. Those little 6.5's are too cool!

 

[Creedmore]

I'll have pictures as soon as I get her put together. I feel like a kid counting the days until Chrismas morning . . . just a few more days.

 

[HTDUCK]

I'll have pictures as soon as I get her put together. I feel like a kid counting the days until Chrismas morning . . . just a few more days.

Yeah and now you got me thinking about pulling the barrel off of the 22-250 and building one of them too.
You're a bad influence my friend . :lol:

I'm looking forward to shooting it too :mrgreen:

 

[338 Ultra]

I have only worked with the standard 260 Rem but did have a great load in my previous gun of 48 gr H 4831sc and a 120 gr Rem CL bullet. I would think the same load with the 120 gr Ballistic Tip would be a good place to start. There are lots of great powders that will do well, my new 260 Rem really likes H 4350 in particular.

Gerry is right on the money I use 48 grains of H-4831 with either the 120 Ballistic Tip or the 125 Partition in my standard 260 and have been using these loads for years. I prefer the 125 for the big deer up here but have shot numerous does whitetails and mules with the 120 Ballistic tips and they kill fast and shoot through have not found one yet.

 

[Creedmore]

I'll have pictures as soon as I get her put together. I feel like a kid counting the days until Chrismas morning . . . just a few more days.

Yeah and now you got me thinking about pulling the barrel off of the 22-250 and building one of them too.

RADD is a terrible and wonderful disease, ain't it. :lol:


I'll save a couple grains and go with the 48gr recommended. Thanks for the feedback!

 

[Creedmore]

At the range this morning doing break in and forming.
Lapua brass
Fed 210M primer
48.0 gr H4831
120gr Nosler BT seated into lands

Forming is going ok, and accuracy is very good but take a look at the brass. The marks arent very deep but have me somewhat concerned. I have fire formed lots of brass, but never seen this.

Sent from my iPhone using Tapatalk - now Free

 

[FOTIS]

Cartridge : .260 Rem
Bullet : .264, 120, Nosler BalTip 26120
Useable Case Capaci: 47.442 grain H2O = 3.080 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Alliant UNIQUE

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 43 12.00 1844 906 31479 3079 100.0 1.651
-18.0 44 12.30 1869 931 32630 3149 100.0 1.624
-16.0 45 12.60 1893 955 33794 3219 100.0 1.598
-14.0 46 12.90 1917 979 34972 3288 100.0 1.574
-12.0 47 13.20 1940 1003 36163 3357 100.0 1.550
-10.0 48 13.50 1963 1027 37369 3426 100.0 1.528
-08.0 49 13.80 1986 1051 38588 3495 100.0 1.503
-06.0 50 14.10 2009 1075 39822 3564 100.0 1.481
-04.0 51 14.40 2031 1100 41069 3632 100.0 1.459
-02.0 52 14.70 2054 1124 42331 3701 100.0 1.437
+00.0 53 15.00 2076 1148 43608 3768 100.0 1.417
+02.0 54 15.30 2097 1172 44899 3836 100.0 1.397
+04.0 55 15.60 2119 1196 46204 3904 100.0 1.378
+06.0 56 15.90 2140 1221 47525 3971 100.0 1.360
+08.0 57 16.20 2162 1245 48860 4038 100.0 1.342
+10.0 59 16.50 2183 1269 50211 4105 100.0 1.325

Results caused by ± 5% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 5% relative to nominal value:
+Ba 53 15.00 2079 1151 44596 3762 100.0 1.404
Data for burning rate decreased by 5% relative to nominal value:
-Ba 53 15.00 2072 1144 42514 3776 100.0 1.430

 

[truck driver]

Hmmm may need to polish that chamber a little. Or it could just be the heat treated color rubbing off. After cleaning and polishing the brass and it still does this than I would be worried and think about polishing the chamber.

 

[SJB358]

That is odd CM.. Wonder if there are some chambering marks left in there? Let us know what it is though. Pretty interested. They do look very cool though.

 

[Creedmore]

Got a message back from my gunsmith, said it's stainless gouging from the reamer. Taking it over to him this afternoon to get cleaned up. Learn something new everyday.

 

[JD338]

Very cool round.
I would use max 260 Rem loads as starting loads for the 260 AI.

JD338

 

[Creedmore]

Thanks for the QL info, FOTIS.

I checked the water capacity tonight, 55.3gr water in an unsized, fire-formed case.

Would you be so kind to run a QL on:

26" Barrel
H-4831 powder
Nosler 120 Ballistic Tip and 140gr AccuBond

Thanks!

 

[FOTIS]

Thanks for the QL info, FOTIS.

I checked the water capacity tonight, 55.3gr water in an unsized, fire-formed case.

Would you be so kind to run a QL on:

26" Barrel
H-4831 powder
Nosler 120 Ballistic Tip and 140gr AccuBond

Thanks!

Sure at what psi?

 

[Creedmore]

For the final round - AI pressure. I searched for a SAAMI value, but only coming up with 60k psi for the 260 Remington. Not sure what 260 AI pressure would be.

Thanks,
-Gene

 

[ccoker]

Interesting round

 

[SJB358]

I ran the QL with the 260 Rem, but changed your case capacity. Your chamber was less than 2 grains more than what QL has as standard in the program, so it should get you close. Let us know how you make out. Very cool round.

Cartridge : .260 Rem
Bullet : .264, 120, Nosler BalTip 26120
Useable Case Capaci: 49.245 grain H2O = 3.197 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Hodgdon H4831 SC

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 87 40.00 2385 1516 30566 7967 82.5 1.510
-18.0 89 41.00 2449 1598 32757 8261 84.0 1.467
-16.0 92 42.00 2514 1684 35115 8551 85.5 1.425
-14.0 94 43.00 2579 1772 37664 8835 87.0 1.383
-12.0 96 44.00 2645 1864 40413 9111 88.4 1.338
-10.0 98 45.00 2711 1958 43384 9379 89.7 1.294
-08.0 100 46.00 2778 2056 46604 9637 91.0 1.252
-06.0 102 47.00 2845 2157 50093 9884 92.2 1.211
-04.0 105 48.00 2913 2260 53882 10119 93.3 1.172
-02.0 107 49.00 2981 2368 58007 10340 94.4 1.133 ! Near Maximum !
+00.0 109 50.00 3049 2478 62505 10546 95.4 1.096 ! Near Maximum !
+02.0 111 51.00 3118 2591 67419 10735 96.2 1.061 !DANGEROUS LOAD-DO NOT USE!
+04.0 113 52.00 3188 2708 72803 10906 97.1 1.026 !DANGEROUS LOAD-DO NOT USE!
+06.0 116 53.00 3257 2827 78717 11057 97.8 0.992 !DANGEROUS LOAD-DO NOT USE!
+08.0 118 54.00 3328 2950 85233 11186 98.4 0.960 !DANGEROUS LOAD-DO NOT USE!
+10.0 120 55.00 3398 3077 92436 11294 98.9 0.928 !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 109 50.00 3212 2750 75363 10620 99.4 1.015 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 109 50.00 2841 2150 51078 9953 87.5 1.201


Cartridge : .260 Rem
Bullet : .264, 140, Nosler AccuBond 39457
Useable Case Capaci: 47.196 grain H2O = 3.064 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Hodgdon H4831 SC

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 86 37.60 2243 1563 31289 7908 85.9 1.602
-18.0 88 38.54 2301 1646 33490 8183 87.3 1.557
-16.0 90 39.48 2360 1731 35861 8451 88.7 1.513
-14.0 92 40.42 2419 1819 38408 8713 90.0 1.468
-12.0 94 41.36 2479 1910 41151 8966 91.2 1.421
-10.0 96 42.30 2539 2004 44109 9210 92.4 1.375
-08.0 98 43.24 2599 2100 47302 9444 93.5 1.332
-06.0 100 44.18 2660 2199 50752 9666 94.5 1.289
-04.0 103 45.12 2720 2301 54486 9875 95.4 1.249
-02.0 105 46.06 2781 2405 58538 10070 96.3 1.209 ! Near Maximum !
+00.0 107 47.00 2843 2512 62938 10249 97.1 1.171 ! Near Maximum !
+02.0 109 47.94 2904 2622 67724 10413 97.7 1.134 !DANGEROUS LOAD-DO NOT USE!
+04.0 111 48.88 2966 2734 72946 10558 98.4 1.099 !DANGEROUS LOAD-DO NOT USE!
+06.0 113 49.82 3027 2849 78658 10685 98.9 1.064 !DANGEROUS LOAD-DO NOT USE!
+08.0 115 50.76 3089 2967 84912 10791 99.3 1.031 !DANGEROUS LOAD-DO NOT USE!
+10.0 118 51.70 3151 3087 91795 10876 99.6 0.998 !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 107 47.00 2982 2764 75734 10159 99.9 1.087 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 107 47.00 2659 2199 51389 9822 90.2 1.280


I also ran you at 63K PSI as a max load. The numbers and speeds are listed so you cannot adjust accordingly.

 

[Creedmore]

Thanks very much!

I just got the rifle back from my gunsmith last night, polished up the chamber to remove the burr. Going to get some more rounds down the tube this week, then maybe do a 500yd ladder test work-up with the 140 AB on Saturday.