Reduced loads question

[reload4ever]

Is it possible to reduce the starting grain load by 20%? For example I would like to use vn110 powder under a 275gr Barnes xpb bullet for my smith and wesson 500 rifle. Vihtavuori shows a 300gr bullet but not the 275. They are using 40grs as a starting load,and I am wanting to use 35grs under the 275 gr barnes bullet. Do you think the pressures will be within the safe limits or not? Thanking all of you in advance.

 

[Yeah]

If you give me your seating depth I'll run it through Quickload.

I don't reload pistol cartridges, but a wild swing at the depth puts it in safe territory.

 

[rockhopper46038]

I am not NEAR the expert others here are on reloading, I'm really just starting, so don't take this as gospel...having said that, physics would dictate that a lighter grain projectile will build pressure LESS quickly than a heavier projectile, therefore the less powder grains you are proposing combined with a lighter projectile should generate safer pressures than the catalogue load you are referencing.

 

[reload4ever]

seated depth is 2.085

 

[451_Detonics]

The problem with some reduced loads is the case load density, in other words how much of the case space is used by the powder. The more empty space there is the more likely the powder will not ignite evenly and this produces a high standard deviation in velocities which in turn affects accuracy. Extremely low case density has even been blamed for detonation in rounds like the 38 Spl using super low loads of Bulleye and Unique tho no true proof has been duplicated.

I would suggest trying Trail Boss if you want a nice reduced load. It is a very bulky powder and nearly impossible to over charge as long as you don't compress the powder. Hodgdon gives this formula...

I am using this for girlfriend loads in my 450 Alaskan and it is very pleasant for even a small person to shoot.

 

[42769vette]

i do a reduced load for my ar. since i use it as a 22 on steriods i load just enough to cycle the bolt. i cant remember what charge i ended up with but it was a good bit below book

 

[kludge]

If n110 is anything like H110, reducing loads more than 3% is not recommended. H110 can do bad things when reduced to lower pressure.

Generally speaking you can safely use a lighter bullet with the same load data, and a 275gr bullet is ~8% lighter than a 300gr, so that's a bit bigger gap than I would be comfortable with.

BUT, you're going the wrong way by wanting to reduce the powder charge... lighter bullets are (speaking generally) loaded with a greater powder charge.

I would recomment calling/e-mailing the powder company and getting their recommendation.

If it were me I'd look at the VV data and IF start is ~10% less than max I would do the following... remembering that internet advice is worth exactly what you paid for it... reduce the 300gr max load by 5% and then work up to max. I might go to max +5%, but it's really hard to judge this since bullet jackets differ from one to the next.

Hoever, if what you really want is a "reduced recoil" load then follow the advice for Trail Boss above or get data for a different powder like Unique or Universal that works well at lower pressures.

 

[Yeah]

seated depth is 2.085

QL says that is a compressed load, 130% @ 60,800 PSI. Well on the safe side at 60,800 PSI though. 2292 fps out of a 26" barrel.