I have a new 270 and decided to load up some cheaper ammo to sight it in. I loaded twice fired Winchester brass with 130 gr. Sierra SBT's. I used a powder I have never used before which is IMR 4831. I used Lyman's starting load of 53 gr and decided to use some MagTech Large Rifle primers I had bought during the big shortage. My OAL is 3.250. That first shot ran 3255 fps, flattened primer, and small split in the neck. This is way over speed for their max load in the book. I see Lee's shows 50 gr. start and 56 gr max. Anyone have any ideas since I am using a new powder and a new primer?
I have used IMR 4350 and win primers in my other 270.

looks like you need to recheck your load, or your scales.. I load alot of .270 win. with 56 grs of IMR-4831 and 54 grs of IMR 4350 with the 130 Sierra spbt & WLR primer, this is not a hot load.. and I have never got that kind of velocity, it usually runs around 3030 fps in a 22" barrel..

I agree with vines. Something looks really wrong here. I would expect those velocities with something closer to 60gr of IMR4831.
Where did you get the powder, and have you shot it in anything else?
In the rifle New, out of the box, or is it just "new to you"?

Cartridge          : .270 Win. (SAAMI)
Bullet             : .277, 130, Speer BTSP 1458
Useable Case Capaci: 63.168 grain H2O = 4.101 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length      : 24.0 inch = 609.6 mm
Powder             : IMR 4831

Predicted data by increasing and decreasing the given charge,
incremented in steps of 0.87% 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

-08.7   94    52.50   2873    2383   46742  10741     99.1    1.257
-07.8   95    53.00   2899    2427   48074  10815     99.3    1.241
-07.0   96    53.50   2925    2470   49442  10886     99.4    1.225
-06.1   97    54.00   2951    2514   50849  10953     99.6    1.209
-05.2   98    54.50   2977    2558   52294  11016     99.7    1.193
-04.3   99    55.00   3002    2602   53781  11075     99.8    1.178
-03.5  100    55.50   3028    2646   55308  11131     99.9    1.163  ! Near Maximum !
-02.6  100    56.00   3053    2691   56879  11182     99.9    1.148  ! Near Maximum !
-01.7  101    56.50   3079    2736   58494  11229    100.0    1.134  ! Near Maximum !
-00.9  102    57.00   3104    2781   60155  11272    100.0    1.119  ! Near Maximum !
+00.0  103    57.50   3129    2826   61863  11312    100.0    1.105  ! Near Maximum !
+00.9  104    58.00   3154    2871   63620  11351    100.0    1.091  ! Near Maximum !
+01.7  105    58.50   3179    2916   65428  11390    100.0    1.078  !DANGEROUS LOAD-DO NOT USE!
+02.6  106    59.00   3203    2962   67288  11427    100.0    1.064  !DANGEROUS LOAD-DO NOT USE!
+03.5  107    59.50   3228    3008   69202  11465    100.0    1.051  !DANGEROUS LOAD-DO NOT USE!
+04.3  108    60.00   3252    3054   71172  11501    100.0    1.038  !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    103    57.50   3168    2897   65470  11166    100.0    1.079  !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 3% relative to nominal value:
-Ba    103    57.50   3084    2745   58269  11448     99.8    1.134  ! Near Maximum !
   

New info. I shot an old 58.7 gr RL 22 load with win primer and the 130 and got 2805 fps but do have a very slightly flattened primer. I then tried a starting load of 49 gr of 4350 with the MagTech and got 3025 fps and another split neck. The gun is a brand new Sako A7 stainless.

What chronograph are you using?

It looks like the RL22 load with the Winchester primer is close to where it should be. If anything, it's a little slow, which is not unusual for a Sako/Tikka rifle.

I would suspect the MagTech primer could be the culprit. If I had some CCI200 on hand, I'd load the H4350 load with the CCI primers, and see it they delivered the velocity I would expect. If not, I'd still try the starting H4350 load with the Winchester primers and see how the results differ.

I've never used MagTech primers. Are they labeled Super Hot Magnum with a skull and crossbones by chance?

The MagTech primers are marked "No. 9 1/2 Large Rifle Primers" I am out of Winchester primers unless I have a piece of a box somewhere. I do have a thousand of the CCI which I have never used either. Guess I will give them a try. I have always tried to be consistent and use Winchester primers but sometimes you take what you can find.

First, your split necks have nothing at all to do with pressures. Necks split when they are work-hardened (or started out too hard in the first place.)

Second, judging pressures from the appearance of the primer is largely an old wives tale -- that is unless the primer has a gaping hole around the firing pin indentation or is rolling around in your magazine after the shot. Simply appearing "flat" is more a function of how much headspace your loads are leaving in the chamber, thus how much the primer backs out prior to the expanding case catching up with it. If you have full length sized your reloaded brass by ramming the shell holder hard against the die you will almost invariably get very "flattened" looking primers, even with quite modest pressures.

Consumer chronographs are subject to error in various ways, particularly the little folding variety like the Chrony. So don't rely on an inexpensive chronograph to provide you with an aboslute velocity, only a relative one.

The load you list with IMR-4831 should not genertate excessive pressures. If your bolt lift was not tight and there were no other signs of excessive pressure, then I think you may be jumping to a conclusion based on the high velocity reading. Or maybe not. High pressure could be caused by an overly long case which is clinching the bullet when chambered, and by a couple of other more obscure problems.

I'd advise shooting some factory loads through your rifle to get a baseline on both your chronograph reading and on the appearance of the primers.

Hope this helps.

Thanks for the help. I do not worry much about the primers but the high velocity and a little extra recoil concerned me. I must admit the cases were in no way hard to extract. I did finally fire a Hornady factory load to go with the known reload and my cheap chrony gave expected velocity readings. The Hornady SST primer did not flatten any. I May back off on the resizing die a turn or so. BTW I have, 12 more pieces of brass with the MagTech primers. How do I extract them safely?

quote:

BTW I have, 12 more pieces of brass with the MagTech primers. How do I extract them safely?

Pull the bullets if not already and just shoot the primers.

I have decapped live primers but it is not good practice.


Cal30

Check your scale.If you don't have any calibration weights,weigh some of the bullets and see how close to 130grs they weigh.This is not a way to calibrate your scale,but the bullets should weigh + or - .5gr of 130grs.This will at least give you an ideal if your scale is way off.There is no way you should be getting those kind of velocities with that load,so make sure you double check everything.

Good idea on using the bullets to check the scales. And I had thought of firing the primers since my last post and it is good to have someone confirm it. I think I will put those MagTech primers back in the ziploc for storage, and may even do that to the CCI's if I find some Winchester primers this weekend. All my loads have been developed with Winchester and I hate to start over with new primers.

How far are you off the lands?

Arky

I doubt it is your primers, like others havr said check your scales or powder charge. Heck you might even be be working at or near Max with your load and have made a simple overlook on powder such as IMR vs H powder.

Myself I have done that when I first started and the old manuals did not specify amoung the two.




Cal30

quote:

IMR vs H powder.

IMR 4831 is alot hotter the H4831.....so that shouldn't be the issue.

It is IMR 4831. I just broke the seal on the can. I do not know how far off the lands I am and there is not even a scope on the gun yet. I was just going to develop a moderate load with these ingredients to sight the thing in rather than use my Acubond loads I was using in the other 270. The scales appear to be correct checking with the 130's and then a 75 gr. bullet. The scope did cone in yesterday. The VX-II's are on sale at Cabela's.

Scary stuff Arky!

I have a tub of H4831 that seems a lot slower burning than either the manual or QL say it is, upto 200fps slower in some cases with matching indications of low pressure.

Could it be possible that you're simply got a very fast, for IMR4831, lot of powder?

If the scales check out, the throat is clean and factory ammo shoots to where it should there's nothing else I can think off.


PS. A thought; the high pressure case, had you trimmed it before loading?

The cases had been trimmed 1 time but not since the last time shot. I show the cases had been trimmed to uniform length just a tiny bit over trim to and fired 2 times. They had been loaded about a grain under max both times. I will return to IMR 4350 for the time being.

I tend to agree with Stoncreek on this. Although IF, by chance, you've accidentally mixed up the load data for IMR-4831 with H-4831, you should still be safe. I've never used the primers you speak of but would tend to think they are fine. Your cases should be trimmed to 2.530" as noted in the latest Sierra manual. The max. OAL, should be set to 3.300", again. per that bullet listed in the Sierra book. Interpolating the velocity from my Sierra manual, you should be getting about 2835 fps with that bullet. As a side note, I never use a 130 gr. bullet in my .270 Win. but I think you should have good luck with your choice. BTW, the "Accuracy Load" listed in the Sierra manual is 56.7 gr. of Rldr-22 for an estimated vel. 3000 fps.
Good Luck.
Bear in Fairbanks