Filler Question

I've seen references to a filler known as grex/psb. I've checked previous threads to find out what it is with no success. I tried googling the term, but all I came up with was after market auto parts. Then I found a thread in this forum that said that grex was mainly used as a shot buffer. Well OK, off to Midway. No grex at Midway, but they do carry three products from BPI Industries called Mix47, Original and Bismuth shot shell buffers. BPI claims that the Original is compatible with centerfire applications.
So, my question is: has anyone used BPI Original in centerfire rifle applications with good results? Here in NH with our summertime humidity, such that oyster crackers have a shelf life of about two weeks once opened, I won't use cereal fillers. The descriptions I've read of dacron use have put me off the use of that material, at least for the time being.
Bottom line, I'm not asking for a specific load for a specific rifle. I DO understand that fillers raise internal pressure. And if I come close to a max load (one grain at a time) during winter, that I will have to start at the beginning again come summer. With the full understanding that I have the sole responsibility of producing safe handloaded ammo for my guns, can anyone recommend any of these three produts from BPI. Thank you.

Ken

Ken, you should try the one recommended and report back. Most any polyethlene in small ball shape granules SHOULD work fine. ... felix

monadnock#5,

PSB, interested- pm me you address for a sample.

Jon

http://www.surplusrifle.com/shooting...ller/index.asp
This is the most info I've found on it so far.
I've tried it and it works sometimes.

monadnock,

These fellows have worked with PSB & cast boolits.

http://www.surplusrifle.com/shooting...ller/index.asp

I don't think Grex is available anymore.

Let us know how the PSB works for you.

Regards,

..................Grex is NLA from Winchester as a component. It was a coarsely ground polyethelene filler. The only other filler I've used was from Graf & Son and was called 'Super Sam'. This was very different then the Grex I'd used. The SS is very finely divided polyethelene and is very tiny balls. Kinda like surplus WC820 powder.

Where I doubt that Grex would have had a chance in hell of infiltrating a powder charge, SS on the other hand would. Especially an extruded powder that wasn't compressed or vibrated before adding the SS.

For a filler I'd use dacron over anything I felt needed a filler. For SS or the like I would use it only on charges filling at least about 80% of the case, and then it would be compressed atop a compressed or vibrated powder charge.

.................Buckshot

Fillers are used for two purposes. Your choice should be made based on the goal you are trying to achieve.

The first purpose for filler is to control the position of the powder to improve the burn. Things like dacron, kapok, toilet paper are used for this purpose. These are space fillers.

The other purpose is for protection of the bullet. Grex, PSB allow either higher pressures with the same hardness bullet .... OR .... allow a softer bullet to be used at the same velocity. These applications tend to be for hunting.

For this purpose, I use the Origional. But only under compressed situations for shells that will not be stored. Like for hunting.

I always test my loads both before and after season just to see what effect all that vibration has had. Accuracy and the chrono both say they are the same before and after. So if it mixed, it didn't alter much. And for high performance cast loads, all I burn are stick powders.

If seperation concerns you, just use a little tuft of something fluffy, like dacron, over the powder before you add the grex. Then compress it.

:coffee: ---Nice job Bass -- all good info.----there is a third use for filler in the case of bad boolit fit as is found mostly in .303---The filler trying to get out of the barrel before the boolit will help to stabilize this situation of a bad boolit fit ---this is covered on the .303 sites---can be used for any cal. but the .303 seems to be a good candidate for this. I have done a little work with fillers ---Interesting but requires caution---

Some use a filler to raise pressure----(not common)

Some use a filler to keep gun and cases clean

Mag:castmine:

I have used PSB filler with medium to slow burnng powders with very good sucess. Best 30-06 load I have found to date is 49/WC872 plus 1 to 1.5ccs of PSB depending on the bullet.

To be truthful I have found 2400 without PSB to be almost as accurate without the hastle of compacting the powder charge and using the filler.

I've done alot of work with .303's and I'll agree with Mag 01,they do shoot better with filler.Lee's are a law onto themselves PAT

I bought some poly fiber pillow stuffing to use as filler. It is fiber like cotton. Did I get the wrong stuff or is this being used also.

Thank you to all who responded to my question, and in particular to Jon K. I saw your note on the bottle cap, and your wish is my command. I had anticipated that getting my question answered would be something like pulling teeth. Sometimes I enjoy being wrong about something, and this is one of those times.