can changing brand of bullet (not grain) cause unsafe pressures?

[newdad]

im still fairly new to reloading, so far ive mainly stuck to 45/70 and 223 and had good luck at finding accurate loads in both. I plan to start reloading for my new to me 30-06 and am having trouble finding load data for what im wanting to do. I have about a pound of benchmark powder on the shelf and I know it isn't the ideal powder for the 30-06 but I would like to use it. say for instance if the load data called for a starting load of 47 grains of powder and a sierra 150 gr bullet and I substituted a 150 gr Winchester power point, what would that do to pressure? thank you for any help

[shot1]

Different makes of bullets can raise or lower the presser some but if you are using a starting load and then working up you will be OK. The only time to really watch subbing makes of bullets is when you are at or around max loads. If you want that 30-06 to sing with a 150 gr bullet get you some IMR 4064 and use 51.2 grs. This shoots lights out with every cup and core type bullet in every bolt action 30-06 I have ever tried it in and that is a considerable amount of rifles.

[hillbill]

ive never had a problem with switching bullets.in good strong modern firearms.i will start out a grn or two lower, load 5 shells,shoot and check for pressure signs..ive often used data for heviaer. bullets with light bullets and worked up from there also

[Catfish]

What shot1 said.

[newdad]

thanks fellas, appreciate it.

[Bigeasy]

Different makes and types of bullets of the same weight can and will change pressure levels.  Variables include jacket material and thickness, bearing surface, seating depth as canulatures vary.  A cast bullet, all else being equal, will usually show less pressure then a jacketed bullet.  A "hard" solid bullet, like the Barnes TSX, especially the earlier ungrooved version will show more pressure compared to a common cup and core bullet.
 
Sticking to starting loads for a particular bullet weight, you are usually safe with about any bullet style.  But when you start working up, bullet type becomes more important.  Judging pressure signs without testing equipment is hit and miss, at best.  That is why it is smart to stick to tested, known safe loads as found in reloading manuals.
 
larry

[LanceR]

The advice you have so far is good.  Remembering that most load data is published by the bullet makers it makes sense that they will tell you to use the data for their bullets only.  Why would they test anyone else's bullets?

If, however, you talk to the powder makers they will generally tell you that you can readily swap bullets of the same weight and (importantly) the same construction.

As already stated, gilding metal solid (Hornady GMX) and gilding metal jacketed bullets will tend to be in the same pressure range while copper solids with the same profile will result in higher pressures due to the harder material being formed to the lands and grooves of the bore.

Similarly, a long tapered may result in different pressures than a short flat nosed bullet of the same weight due to the possible change in bearing surface.

While researching an article a few years ago I talked with the tech folks at Hodgdon, Alliant etc and was given pretty much the same answer by each person I talked to; bullets of similar construction and shape are safe to interchange with conservative starting loads.  After that you are on your own.  This really does not differ much from what we should be doing anyway.

Good luck.

Lance

[wncchester]

"Different makes of bullets can raise or lower the presser some but if you are using a starting load and then working up you will be OK. The only time to really watch subbing makes of bullets is when you are at or around max loads."
 
That's the sum total of it.  About the only way such a change would be dangerous is if you're loading  on the ragged edge of a KABOOM anyway but proper work-up and testing will handle it.

[Ron T.]

im still fairly new to reloading, so far ive mainly stuck to 45/70 and 223 and had good luck at finding accurate loads in both. I plan to start reloading for my new to me 30-06 and am having trouble finding load data for what im wanting to do. I have about a pound of benchmark powder on the shelf and I know it isn't the ideal powder for the 30-06 but I would like to use it. say for instance if the load data called for a starting load of 47 grains of powder and a sierra 150 gr bullet and I substituted a 150 gr Winchester power point, what would that do to pressure? thank you for any help

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At this point, you can see that your question has mostly been answered, but what you might still be wondering is "why" does different makes of the SAME WEIGHT bullet cause chamber pressures to vary!

As was mentioned previous, it's the type (hardness) of the metal in the JACKET of the bullet plus the length of the individual brand of bullet's BEARING SURFACE which creates the difference in the chamber pressure the bullet generates.

And so, as you can see... simply because two bullets are the SAME weight doesn't mean they create the SAME chamber pressure when fired.   


Strength & Honor...

Ron T.

[newdad]

thanks for all the help fellas, anything I load is always at starting loads and I never get anywhere near max load data.

[Dand]

One other detail that hasn't been mentioned here is that at the same grain weight and basic construction, different brands, even manufacturing lots of the same brand, may differ slightly in diameter - another source of pressure differences. Its tedious but mic a sample of different brands and you may observe this yourself. I think if you search Handloader Magazine you may find some articles on this. The Lyman reloading manual may have a discussion - don't recall for sure. 


Usually I don't think the differences will cause catastrophic pressure differences unless you're working close to max. But in some cases a mid range charge with a "fatter" bullet might get you close to max before you expect to.


Still, I have worked up some loads in my 300 win Mag that work fine with 180 gr Speer Hot Cores AND 180 gr Nosler Partitions - tho I have dropped off about .5 grs of IMR 4831 from a few years ago as I thought the brass was showing signs of pressure after 3-4 loadings.


I have found very good results in my 2 30-06 with 54-55 gr of IMR 4350 and nearly any 180 gr bullet - EXCLUDING any of the solid brass /bronze/gilding metal bullet.


These days I tend to load a little below apparent Max just to be safe, esp if I get better accuracy and its usually easier on my shoulder.
HTH