223 / 60HP / H335 question ?

[Jasonsmack]

Trying to make a load work and I am a little confused. I used the Hodgon magazine for my baseline for the loads. I went up to 24 grains of H335 for a max load (according to the magazine) with good accuracy but the bullets were SLOOOW. I only was able to chrony a couple above 2800fps. I was shooting the same bullets in the same gun last year with speeds near 3200, and they were almost as accurate as a laser.

Now my question is this; Why does the Hodgon magazine show a max load of 24 grains of H335? Some other internet sources, including some Sierra data I found, are showing max loads of 25.6 and greater for the H335/60 grain Sierra hollowpoint combination. Some other places show even greater max loads. Why does the Hodgon data show the low max load for H335? Their max load for the H4895 was certainly not conservative.

I assume that if Sierra is showing a max load of 25.6 grains of H335 behind their 60grainHP that it should be safe in any modern gun, right?

 

[curtmg]

NO, it was a safe load in their test rifle barrel. It is known as a MAX LOAD for a reason. IF you work up to that load and don't get any pressure signs, and velocity is where it should be, then it might be a safe load in your rifle, but if funny stuff starts to happen before you get there, then it is not a safe load in your rifle. My 300WM shows signs really drastically if I try anything close to a max charge (flat primers, blown primer pockets). Just because Sierra found it to be safe in their rifle does not mean it is safe in every rifle. Hodgdon's lists a lower charge, as that is what their testing found to be a max load, in their test rifle. Every gun is different, two guns same model built consecutively, might have different pressure tolerances.

 

[Jasonsmack]

Understood but; is the pressure of H4895 that much lower than that of H335 then? The Hodgon magazine has the pressures listed and it does not really indicate a large difference in pressures. I am shooting at least 400 fps slower with the H335 than the H4895 with no pressure signs on either load.

This is how it is/was loaded:
OLD LOAD-> 25.4 grains of H4895, 60 grain Sierra, flying at average of 3227 fps. (53 more fps than Hodgons indications)
NEW LOAD-> 24 grains of H335, 60 grain Sierra, flying at average of 2765 fps. (310 fps slower than Hodgon's indications)

Both loads shoot accurately, and are being shot from the same gun. The gun is a Tikka T3 with a 1in8 twist rate. I do shoot the gun out to longer ranges alot and need to push the velocity up to maintain the lower drop rates to match my scope reticle. The H4895 was bang on, I can probably get away with a little less speed but a 400 fps drop is not going to cut the mustard. I need to get away from the H4895 due to lack of case capacity combined with the 60 grain bullets, it makes it impossible to load these cartridges short enough to fit into other gun magazines like my AR180/AR15's. The H4895/60Sierra combination barely fits into a Tikka magazine and often leaves a ring on the projectile from the seater pressure as it compresses the powder. Plus the H335 measures more way accurately with less crunching and nonsense than the H4895 does in my Hornady powder measure.

 

[rnbra-shooter]

It sounds like the H335 you are using might be an unusually slow lot. You can probably safely work up your load to 3100+ fps. If you are feeling uncomfortable because this contradicts at least one printed source of data, then good; it shows that you are cautious, and are actually thinking about this stuff! In which case, you are probably capable of safely and prudently doing this load development.

 

[Jasonsmack]

I was wondering about the powder, but I do not have enough experience with it to know if there could be variances. I will work up the speed on the stuff I have. I have two cans of it so I will check the batch numbers and see if there is any difference.

Thanks.

 

[windage]

I am thinking you might have done this already but have you checked the chrony? There was another guy on these forums complaining about his chrony being 300fps slower then what it should be reading.

 

[Jasonsmack]

I checked the loads on the chrony back to back so I am assuming that the chrony is right. The 4895 loads were fast and the 335 loads were slow, all shots were done within about an hour. I even shot a few of the 4895 loads in between my 335 work ups to make sure.