fillers for nitro express

[skydiver386]

I would not use anything but a firm soft filler no type powder with the chance to mix with the gun powder

I don't think it's fine enough to mix with the gunpowder if filled and seated properly, especially if you use the larger sizes.

If it were fine like talcum powder I could see that, but this is more like granules. It's primarily purpose is to be used to buffer lead and steel shot in the wad for shotgun loading.

Roy Weatherby, Rocky Gibbs and many other Wildcat cartridge makers used Grits, Cream of Wheat and other granular fillers over light loads of fast burning powders to fire form the brass and move the shoulder forward, etc., which leads us to another point.

I see one post concerning the wadding material becoming jammed in the shoulder area and raising pressures. Possibly not so important in straight walled or Nitro Express cartridges but definitely possible in bottleneck cartridges. I've seen one manufacturer that specifically warns against using its vegetable fiber wads in any cartridge with a large degree of taper or a bottleneck shape. A granular filler eliminates this concern.

No matter what is used, a handloader should be cautious and watch for signs of excessive pressures.

 

[Esoteric Junkie]

any sentiments/ experience using dacron vs foam fillers for nitro express cartridges?
specifically, 450 3 1/4

thankx

Load whatever powder charge and insert backer rod. Cut off at the case mouth with a razor blade then seat the bullet.

EJ

 

[matt85]

I use circle fly wads for my 8-bore rifle. They are easy and inexpensive. My NFB loads use four 1/2" fiber wads and a couple card wads to get the bullet sitting where i want it.

 

[Ray B]

For 50 years I've reloaded reduced charges in small bores (22/30-30 to 375H&H) by adding varying amounts of kapok on top of the powder. depending on the case, about 2 grains was sufficient. The loadings never indicated a problem and totaled well over 10,000 rounds. While I am comfortable with the kapok loads, following the advice of several on the forum and a few books, I use foam backing rod cut to 1" lengths as filler in the 470 over IMR3031 and under a 500 grain Woodleigh.

 

[SStomcat]

following the advice of several on the forum and a few books, I use foam backing rod cut to 1" lengths as filler in the 470 over IMR3031 and under a 500 grain Woodleigh.

Do you mind sharing the type of backing rod used, is it closed or open cell?

 

[Jefferry404]

I am using N165 in my 416 Rigby and 505 Gibbs to get near 100% load density at within spec psi without filler.
For the 450, with 500gn Woody, u might get 2130fps within psi spec. at 100% density

 

[AZDAVE]

started off using Dacron and moved to foam backer rod. and didn't look back. Did also try plain old toilet paper between the switch and liked it better than Dacron but got more consistence results with foam.

 

[Ray B]

Do you mind sharing the type of backing rod used, is it closed or open cell?

If I can get the photo to post.

Evidently not- I'll lookup the photo and post details

 

[Ray B]

It's called MD Backer rod Medium size, 1/2" diameter. I got it at a local hardware store but Home depot also had it.

 

[SStomcat]

It's called MD Backer rod Medium size, 1/2" diameter. I got it at a local hardware store but Home depot also had it.

Yes, and I think it probably adds to the fact that closed/open cell "may" not make any difference.

 

[Troubleshooter]

My buddy Mac gives me a ton of grief for spending the extra effort to punch out the foam sheet which I did because I was trying to make the wads cut from open cell backer rod as close to the #2 Kynoch as possible. Problem being, without some kind of cutting jig, you’ll never get precise, repeated length and damn near impossible to get pretty square ends, they always seem slightly off. That said, shooting I can’t ascertain a bit of difference between using the Kynoch, those punched from the 1” foam sheet, or those cut from backer rod, and that’s with shooting multiple hundreds of rounds through 7 different Heym and 1 Westley Richard’s doubles as well as a 505 Gibbs Breeding bolt gun…over chronograph where I’m looking at ES/SD working up loads and same when shooting for practice/fun.

Think Mac is 100% accurate that the slight difference in length and cut angle doesn’t matter one bit…which is why he knocks out several dozen in a couple minutes with a big pair of scissors. My OCD-inclined brain won’t allow it though.

End of the day, I’d suggest taking a little time to find proper open cell foam like that used in the Kynoch #2 wads, in real 1/2” or 5/8” diameter, or punch same from a 1” open cell sheet. While I can’t bring myself to cut them with scissors, I am better about knocking them out quickly with a Havalon, but still trying to get them as square as possible. I find the sheet/punch production faster but both shoot the same.

Good advice on the open-cell foam. It seems like one could fabricate a serviceable cutting jig from some scrap lumber and an exacto knife. Might have to give it a try for cutting the foam backer-rod.

 

[deewayne2003]

I had switched before that just for ease of loading. Was surprised to see their results when they published them.

If I recall they also got some goofy pressures or inconsistencies with 3031 powder as well in the Nitro cases.

Never heard anything about goofy pressures with 3031, what I have heard about 3031 is various stories to the effect of…..

“My cousins aunt Sally was in Mozambique 45 years ago and she saw a double rifle blow up and kill 27 people at one time because the ammo was loaded with IMR3031!”

I keep hearing these magical stories about pressure and blah blah blah…….

Yet, both Ken Owen and JJ recommend 3031 on a regular basis for double rifles; especially Ken Owen who says it’s one of the most consistent powders made and…….
“A whole hell of a lot more stable than the Cordite these calibers were developed and loaded with!”

I’ll take the word of master gunsmiths capable of building and regulating double rifles over the…..

” I heard that(insert rumor) was unsafe” crowd

 

[MacJenkins]

Never heard anything about goofy pressures with 3031, what I have heard about 3031 is various stories to the effect of…..

“My cousins aunt Sally was in Mozambique 45 years ago and she saw a double rifle blow up and kill 27 people at one time because the ammo was loaded with IMR3031!”

I keep hearing these magical stories about pressure and blah blah blah…….

Yet, both Ken Owen and JJ recommend 3031 on a regular basis for double rifles; especially Ken Owen who says it’s one of the most consistent powders made and…….
“A whole hell of a lot more stable than the Cordite these calibers were developed and loaded with!”

I’ll take the word of master gunsmiths capable of building and regulating double rifles over the…..

” I heard that(insert rumor) was unsafe” crowd

So your fine with Michael and Sams data in regards to Dacron. Which you state was some compelling information that helped you make the decision to switch to foam. But when I bring up that I recall they also got some concerning data on 3031 that's "magical stories". Makes sense.

 

[grand veneur]

Using a powder like the IMR 3031 for reloading big Nitro Express cartridges is not entirely without risk. While it is certainly a suitable powder for reloading this large-capacity cartridges, the way you use it matters. I don't know exactly what various gunsmiths have recommended, but in all cases, the empty space in the case must be filled with somewhat so that the powder is slightly compressed. The optimal load density for a cartridge case is 100%, and the lower that level is, the more caution is required. The powder needs to burn from back to front after ignition, but not erratic, scattered loosely within a too large space, with step by step explosive pressure spikes inside the case. That is the theory. In practice, things might often go well, but it is better to stay on the safe side and to use a filler.

 

[deewayne2003]

So your fine with Michael and Sams data in regards to Dacron. Which you state was some compelling information that helped you make the decision to switch to foam. But when I bring up that I recall they also got some concerning data on 3031 that's "magical stories". Makes sense.

Yes you are 100% correct......

The DATA presented tells a logical path to lower pressure with the same velocity and easier to load = WIN WIN situation that is hard to ignore from the data presented.

"If I recall" = From my own admission I may not be remembering this correctly and I'm not posting the data where it was found, but there is a chance that what I am saying may or may not be correct.

So YES as stated before, I will trust the decades of experience of both JJ Perodeau & Ken Owen being in agreement over....... "If I recall"

 

[SStomcat]

Using a powder like the IMR 3031 for reloading big Nitro Express cartridges is not entirely without risk. While it is certainly a suitable powder for reloading this large-capacity cartridges, the way you use it matters. I don't know exactly what various gunsmiths have recommended, but in all cases, the empty space in the case must be filled with somewhat so that the powder is slightly compressed. The optimal load density for a cartridge case is 100%, and the lower that level is, the more caution is required. The powder needs to burn from back to front after ignition, but not erratic, scattered loosely within a too large space, with step by step explosive pressure spikes inside the case. That is the theory. In practice, things might often go well, but it is better to stay on the safe side and to use a filler.

Interesting, I have factory loaded cartridges from probably all makes including Norma PH using woodlies that my gun came regulated with. I find all of them swift, federal etc have some space in between. How do I know.. simply jerk them and you will find the powder moving all over. So….

 

[grand veneur]

Load densities from 80% to 90%, regardless of the powder used, do not pose too big problems. Many factory cartridges are not delivered with a 100% load density. The situation becomes critical between 60% and 80% and dangerous below 60%, with the risk being significantly higher when using slow-burning powders than faster-burning ones. That is the theory. In practice, a lot depends on the type and quantity of powder used. Handgun cartridges and special cartridges for competitive Benchrest Shooting are a good example for this. However, caution is required with cases that have extremely large volumes, such as those from the old Nitro Express cartridges. Moreover, these are often used in rifles that do not necessarily meet modern standards.

 

[Ray B]

The powder needs to burn from back to front

Not exactly- Elmer Keith and others showed the optimum burn was from front to back. this was accomplished by having a tube placed over the primer flash hole so that the primer's flash was directed to the front of the powder charge, ignited near the bullet base then burnt back toward the cartridge head. the problem with the system was that manufacture has some real issues.

The point is that the powder needs to be lit as one side and burns through to the other. the problem occurs when the powder is laying flat in the case and only fills half of it. then the primer fires and flash shoots over the top of the powder, igniting the entire charge so the only aspect of the progressive burn is the little distance from top to bottom- the result is a pressure curve that is much faster that the powders design.

 

[grand veneur]

"Needs" was perhaps not the right word to describe how the powder burns after ignition. It is well known that there are better burning processes, but difficult to realize.