Pressure signs on starting loads or factory?


Peter M. Eick
January 23, 2010, 07:35 AM
First the Facts.
The rifle is a 25-06 sendero remington 700.
It gives some pressure signs with factory ammo. Most commonly ejector marks. This occurs on most rounds, but not every one fired.
It was 60f on the range and very windy.
The load was straight from the seirra manual. I actually duplicated it exactly to run this experiment.
45.5 grns of IMR4350 with the 90 grn JHP (max load is 53.7 grns).

I get ejector marks and sheared ejector holes with this, the starting load. And the accuracy was poor, 2" patterns for 50 shots.


Now, it gets odd. I can load 53 grns of IMR 4831 with the same bullet and setup and no pressure signs (max load is 54.9 grns), accuracy was good 1" single hole for 50 shots.

Why? If the rifle was at fault, would it not have the same pressure and velocity limits?

My conjecture is that my gun just does not like 4350 or I have a fast lot of the stuff. This is unfortunate because most manuals list 4350 as a "go to" powder for the 25-06. Otherwise I have a hard time explaining why I can go a near max load with 4831 yet I cannot go a starting load with 4350.

As another tidbit, I was shooting 52 grns of 4831 with a 100 grn spire point and got great accuracy and no pressure signs.

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January 23, 2010, 10:13 AM
Your problem is odd, but not unheard of, like you said your rifle just may not like IMR 4350. IMR 4350 is a little faster than IMR 4831, so you may be getting the pressure spike that gives the symptoms you state. The 25/06 is really a magnum cartridge, it just doesn't carry the name. I find that my 25/06 like slower powders, like IMR 4831 and slower. I've had good results with IMR 7828 with the 110-120 gr and IMR 4831 with the 90-100 gr. One powder that I have yet to try is Reloder 17, from what I read it is a good powder for the lighter weight bullets in the 25/06. Below are some links to look at. Check out that Alliant link for the 87 and 100 gr loads for Reloder 17, look real good velocity wise if it will group, it may be a good powder for what you want.

Jimmy K

January 23, 2010, 02:14 PM
CAUTION: USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information. My guess and some info from my old loading manuals.45.5 grns of IMR4350 with the 90 grn JHP (max load is 53.7 grns). Your below the - 10% starting load. This caliber has been "erratic when using bullets heavier than 87gr. with some powders. ":confused: " If any signs of pressure are encountered with starting loads, try another powder":confused: as you have. You have heard of KABOOMS with light charges of powder, this may be what you are experencing. An increase in the powder charge might not show pressure signs.??:confused: This is my guesss :uhoh: Look for other pressure signs, hard bolt lift. The web expanding. How the primers look.

Peter M. Eick
January 24, 2010, 05:05 PM
I have to admit I did not consider that I was too low of a load on 4350. I will have to bump it up to hodgdon's minimum and try again. I figured seirra's starting load was a good safe one to start with.

Thanks for the advice.

January 25, 2010, 09:41 PM
Just so you know the Hornady reloading manual shows 45.7gr of IMR 4350 for 100gr bullet and Lyman shows 46.5gr of IMR 4350 for a 100gr bullet, their is such a thing as too low of pressure. Lyman recommends IMR 4350, while Hornady states that IMR 4831 performs well when loaded to 90% of the max load.

January 26, 2010, 10:30 AM
Examine the powder closely!
I suspect that it may be contaminated or deteriorated.
I had some surplus H322 detreriorate on me some years back. Likewise, some H450 that originally gave some superlative accuracy with some 180gr Speers in an '06, but two yrs later yeilded a stuck bolt and a buldged case that looked like a belted magnum case, minus the primer. I had to pull all the loaded ammo, and toss out 5+ pounds of powder. If your powder smells like an old aspirin bottle, or vinegar, toss it. Also, look for different powder granules. Extruded and spherical grains is easy to spot..... (unless it's Hybrid V100.......)

I also have on two occasions dumped some powder back into the wrong container......
**IT happens...

I've even got some surplus WC860 thats got some occasional large extruded granules mixed in. Came that way !!!

A friend had some bad Winchester .25/06 120gr P-P Ammo he bought several years ago when on an out of town hunt where he got to Pensylvania and discovered he'd left his ammo on Georgia... It was doing what your load is doing. He pulled a round. and discovered that the powder charge was excesive for what appeared to be Winchester Magnum Rifle powder. He sent the ammo back to Winchester and they sent him a certificate for another box of ammo.

BTW, I've gotten excellent results from 4350's in the .25/06. Your results are aberrant.

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