Reloading same weight heads but with different manufacturers?

[vcinri]

The question I have is one of my favorite loads out of my .338 Lapua is 96 gr. H1000 with a 250gr SGK. I would like to experiment with other 250gr. heads.
Hodgdon is telling me max. charge for a 250gr. head is 98 grs. of H1000 and Berger is saying a max. charge of H1000 for their 250gr. head is 90gr., as an example.
I am wondering why such a difference in charge for the same weight head? I certainly don't want to lose velocity or performance.
Different tolerances? Can different manufacturers change pressure that much with same weight heads?
Thanks.

 

[Bigeclipse]

I think it comes down to a couple different things. Some companies may be more conservative on published loads. Some companies test chamber could be different tolerances. Their bullet may have tighter or less baring surface. Whenever I do not have loads for a bullet, I will refer to a bullet of same weight in my manual and start near the lower end and work up checking speed and pressures.

 

[Rick Richard]

Configuration including bearing surface, which influences pressure.

 

[RT2506]

If you will check most reloading manuals or any basic handloading tutorial it will say something to this effect. "If you change anything in a load back off the powder charge and work your way back up." Break this rule at your on risk.

 

[kiwikid]

Just to add a little more confusion into the mix Sierra list a max load of 91.9 grains of H1000 for their 250 gr SGK for the 338 Lapua Magnum. This is listed in the 6th edition of the Sierra manual.

 

[vcinri]

I will be trying 225gr. Barnes TTSX BT and 250gr. Berger Elite Hunters. I wasn't having to much luck with my SGK's on hogs. They weren't opening up and passing right through at all distances.
I am reading some good reviews on both of the copper bullets as hunting heads.

 

[jrock]

The book is a guide line of maximum pressures found during manuf. testing. I always reference as many books and internet data as I can before working up a load. I load the bullet close to the lands and back off about 5% or so from book max and work up. I have yet to find a load that matches book numbers when looking for the most accurate load. Too many variables involved.

 

[Fedwell]

I will be trying 225gr. Barnes TTSX BT and 250gr. Berger Elite Hunters. I wasn't having to much luck with my SGK's on hogs. They weren't opening up and passing right through at all distances.
I am reading some good reviews on both of the copper bullets as hunting heads.

Is there a special reason why you are using a 338 Lapua on Hogs?
Im not trying to be rude just wondering .
seems like a very EXPENSIVE overkill to me

 

[BrianID]

Pressures can change anytime you change the bullet, seating depth, primer, case lot, powder lot, etc. I doubt you would see much pressure changes between 250gr SGK vs 250gr Berger's but you could. A 250 gr mono bullet(Barnes, hammer, etc) at the same seating depth will result in higher pressures and possibly dangerous pressures.

 

[Wilderness Blacktail]

A lot of the loads I have put together in numerous rifles did not have listed data. Most of the time starting at the start data for another bullet is ok but one time I used Sierra data for a Hornady bullet and the second notch, .5gr up from start locked up my gun!!
So dont assume that's its gunna work if you dont drop a couple grains and work up.

Nowadays I always work to fund pressure first so load up 1 of each at 1 grain intervals to where I think I will hit max. Then once I know where I see pressure signs I can fine tune the promising spots with 3 each.
I've saved hundreds of bullets this way and it's super easy and cheap to stay safe and work up.
In ur case I'd def start with the lower numbers if it's not the combo you have on hand.

 

[vcinri]

Just to catch up on the last few replies,

The load I started with came off the Hodgdon website. Max charge for a 250gr. head was 98gr. of H1000.
My load worked out to 96gr. of H1000 and is averaging 3050fps.

The ranch I hunt in Texas has some long range capabilities. After taking my share of hogs at relatively close distances and I wanted to try something different so I set up the Lapua just for this. (very glad I did, lot of fun!) Yes, it is an overkill but fun none the less. Although, I would have never believed a hog would take a solid hit from a .338 Lapua get up and walk away had I not seen it. This is why I'm looking into different heads.
I would also like to maintain the ability of a the.338 Lapua and not have to download to a .338 WM spec.
Thanks for the replies.

 

[jrock]

I'm working my loads for my 338 NM with the 265 ABLRs. I could dig up what I"m using which would be a soft starting point for your load workup. I'm using H1000 and am getting about 3000 fps.

 

[Bingoc]

All good advice from above and from folks that have experienced the differences that are inherent with various bullets i.e., ogive, bearing surface, alloy etc. I always use the manufacturers manual and start 5% lower that the lowest charge listed and work up in 1 grain increments until I see signs of excessive pressure. Be cautious and good luck.

 

[vcinri]

Best to be safe. There must be a reason why different makers call for such a variance in charges of the same powder.
This is where the chronograph is a big help.
Jrock, thank you for your offer, any information would be appreciated.

I may get to the range in next couple of days. I'll post my results.
Thanks,
VC