Question about Backer rod in large volume cases

[Rare Breed]

I am about to start reloading for my 500 Jeffrey. I understand that some loads with this round require a filler, in particular it seems the 100gr of Varget with a 535gr bullet. Either way I understand a lot of people use foam backer rod as a filler. I picked up some but I want to be sure it is the correct one. This one says do not expose to heat or open flame. I want to make sure I have the correct one because I don't want to melt foam to the inside of the barrel. I don't know if that is even an issue but I'm not trying to screw up this new rifle. I will most likely be using H4350 anyway but I think the varget will work well with the 510 CEB solid and the 475 CEB Raptors since it is a faster powder. With those bullets though I expect to be in the 103-105 grain range. I'm also curious to try RL16 in it. Same burn rate as H4350 but fluffier. It does create a bit more velocity so I drop it down by about 10% from the book charge for H4350. I also ans curious if CFE223 will work. It is a bit slower than varget and is a ball powder. It is very close to BLC-2 amd W 760. I will attach a pic of the backer rod I purchasedView attachment 471474

I use Dacron polyester filler and it works great. My personal findings are the following:
1. Be careful of pushing the fiber down tight on powder before seating the bullet
2. I push in just enough knowing when I seat the bullet it will just place the fiber against the powder
3. Too much fiber is better than too little

hope this helps and good luck!

 

[frog stealer]

This is a page out of Sherman Bell’s DGJ article that goes into depth on filler types. This article was based on BPE cartridges, but gives you an idea on relative pressures. I can send a copy of the whole article if interested.

 

[frog stealer]

Oops, forgot to mention: “bb” is piezo reading at bullet base, 1” is reading 1” from breach.

 

[Backyardsniper]

T

Oops, forgot to mention: “bb” is piezo reading at bullet base, 1” is reading 1” from breach.

That ks interesting. I had wondered why no one used cotton balls for this? I figured they would increase pressure very little and according to that graph it appears to be so.

 

[frog stealer]

T

That ks interesting. I had wondered why no one used cotton balls for this? I figured they would increase pressure very little and according to that graph it appears to be so.

I tried using cotton a few times, it seemed to work well, but it didn’t combust, it just shot out the end of the barrel and spread all over the ground, in very small pieces.

 

[Backyardsniper]

After doing a good bit of research I believe I found the answer on the open vs. closed cell backer rod. I believe what I have is closed cell and it does have warning about not.being exposed.to temps over 200° apparently open cell is much more heat resistant. Which may be why I was getting that melted foam residue on the case neck. I will take a trip to Lowe's and locate some open cell and try it. I will attach a link to the info I found.

Interesting Differences between Closed-Cell and Open-Cell Backer Rods

Due to exposure against different weather elements, concrete can develop cracks. In order to save the cracks from worsening further, an option would be Backer Rods. A backer rod is a closed cell, f…

valariearthur.wordpress.com

 

[Rare Breed]

Just got my Kynoch fillers #2 from Trader Keith and reloaded 20 of my 500 NE DR. Love the perfect consistency of each filler. Will be shooting them this Thursday for practice for my Zim Buffalo hunt

 

[frog stealer]

Just got my Kynoch fillers #2 from Trader Keith and reloaded 20 of my 500 NE DR. Love the perfect consistency of each filler. Will be shooting them this Thursday for practice for my Zim Buffalo hunt

Did you get away with using one, or did you have to go with two?

 

[Rare Breed]

One seems perfect. I do not want to over compact the powder

 

[Backyardsniper]

I just ordered a large roll of 5/8" open cell backer rod. I'm hoping it works out well. I just need to find some RL 15

 

[Woodcarver]

Do you guys use a filler for any load that doesn't fill the case? Or only if the powder is less than some percentage of fill?

 

[Rare Breed]

I had great success with no filler and H4831SC on my DR Chapuis 450-400 NE. It was not until Ken Owen regulated my 500DR NE with IMR3031 that I had to use filler. It is so worth it given with this load the recoil is just slightly more than my 450-400 and is a pleasure to shoot

 

[SkullKeeper]

I get a 2x2 square foam piece from Walmart in the weather stripping area. Cut 3/4”-1” widths and use a case body sharpened on one end/filed blunt on the other as a punch (provides a perfect “seal”). Works great and doesn’t leave any evidence in the barrel.

 

[degoins]

great idea

 

[Rare Breed]

I get a 2x2 square foam piece from Walmart in the weather stripping area. Cut 3/4”-1” widths and use a case body sharpened on one end/filed blunt on the other as a punch (provides a perfect “seal”). Works great and doesn’t leave any evidence in the barrel. View attachment 484889

Very smart. I went to Trader Keith’s and bought 100 #2 that work perfectly. You are getting what I got for Pennie’s on the dollar for the same thing

 

[Backyardsniper]

I bought this 500' reel of.5/8 " open cell backer rod from denver materiel, I think it was. I should be set on backer rod for a while. I was $65

 

[SkullKeeper]

Very smart. I went to Trader Keith’s and bought 100 #2 that work perfectly. You are getting what I got for Pennie’s on the dollar for the same thing

I think I paid $4 for a 3 foot piece of that foam. I can get 9 plugs per inch wide section. So about 330 plugs total.