Any firsthand experience using Puff-Lon with boat tail bullets

[jlow]

The idea is to use this to fill the small void in an almost filled case to get more consistent ignition and MV SDEV. The caliber I am interested in using this would be 223 and 308 with a boat tail bullet like an SMK in the 77 and 175 gr range for the two respective caliber. The Puff-Lon manufacturer says that it might cause a reduction in accuracy for boat tail bullet which would of course make this a no-go. Specifically I am interested in is what if anything does this do to the barrel and of course effects on accuracy and MV SDEV.

I know people will want to chime in with conjectures and opinion and how discussion as it is used for other applications. However, I am only interested in firsthand experience here please.

 

[357Mag]

J -

Howdy !

For me, PUFFLON has been great stuff !.

I've shot it in a .357AutoMag carbine, and more recently..... in .35Rem.

For the latter, the bullet was " Dead Center Duplex " .35calibre 200gr SP BT ( rebated boat tail ).

No matter what the powder ( WW296 & H110 in the AutoMag carbine, IMR4759 in Marlin M-336 XLR ),
I first place a small " wad" of tissues over the powder, then add the Pufflon. I've had no filler migration problems.

PUFFLON seems ( to me ) do do pretty much everything claimed of it. My Marlin cleans up w/o my having ot use a bore brush.

The filler can be lightly compressed, and hold its position in the case. I've always compressed the filler, in my loads. * Boat tail produced no unusual challenges, to ( my )use of PUFFLON.


With regards,
357Mag

 

[bigedp51]

The only point in using Dacron fill is to prevent light loads from shifting in the case if the round is tilted. If your talking a almost full case from approximately 85% to over 100% of case capacity I do not see the primer having a hard time igniting the powder.

If your loading an AR15 or M1A your really over thinking a problem that doesn't exist.

KISS = Keep it simple stupid

or

"Everything should be made as simple as possible, but not simpler."
Albert Einstein

 

[jlow]

Hi guys,

Thanks for all your responses!

Dmoran – Not familiar with 45-120, do you use boat-tailed bullets for that? Also quite interested in your statement “I would never use it unless there was a substantial void to fill in a low pressure cartridge scenario only (say under 45k-psi).”

I understand filling the small void with Puff-Lon will cause pressure increases, but my thought is one could always go low and work up using the stuff to keep it safe?

357Mag – sounds like you only have positive things to say about it – thanks!

Bigedp51 – yes, the shifting is why I am thinking of using it. However, it is not because I am worried that the primer having a hard time igniting the powder but here is my rationale.

When the primer ignites, ignition of the powder in a case is not instantaneous but travels from the back next to the primer to the front where the bullet sits. Now the pressure curve generated is directly affected by this progression. If say the powder sits in the case perfectly i.e. like how it would be when a rifle is pointing straight up, the ignition will go evenly from bottom to top. However, if the gun is sitting level and depending on how it and the round had been jiggled before hand, it is entirely possible that the void space may sit not next to the bullet but somewhere in between i.e. like a bubble. Should this happen, when the powder burning from back to front encounter the bubble, ignition will diminished for a short period as it passed through this zone due to the reduce powder in this area, it will of course resume with a passion past it. If one looks at the pressure curve from this ignition, you will see a hiccup (slight drop in pressure) during the phase when the ignition hits the bubble. What this means is the pressure on the bullet will be different and this can theoretically translate to a change in MV and of course all the problems associated with this.

This in a nut shell is the reason why a bottle neck case that is almost completely full will frequently always result in rounds that have tighter and smaller MV SDEV.

Now, because of max load limits, it is not always possible to fully fill cases with many powders, and in those situation, capping the powder with a “wad” (as per 357Mag) and filling the remaining void with Puff-Lon to produce a lightly compressed load will theoretically give you that perfect and reproducible smooth, no-hiccup burn and hopefully tight MV SDEV.

Thus the question and interest.

 

[jlow]

Not sure how one can conclude for someone else that they are “over thinking a problem that does not exist”. For someone to know that, they will have to know that I don’t have a problem which unfortunately is incorrect and I also wish I did not have which is MV SDEV which are not small enough. FWIW, I don’t make work doing something that is not needed.

I agree with you as to combustion and “contained combustion” and the need for safety but what has that got to do with what I am proposing which is to try a technique using a lower charge and work up. Not being nasty or argumentative here, just don’t really understand what you are trying to say.

As for the primer spark, I am using Wolf SRM and LRM primers which German Salasar has already show has one of the smallest flames for the specific reason of a more controlled progressive burn. Not sure what evidence you have that would lead to your conclusions.

I don’t have any problem with anyone coming with reasons that tells me not to try this, as it is one of the two reasons I posted this question on the board. But it is only really helpful if I can understand the rationale.

 

[jcampbellsmith]

The idea is to use this to fill the small void in an almost filled case....

Surely the obvious answer is to use powders that have fill ratios of greater than 100% and shoot compressed loads? Keep in mind that each operation introduced into the reloading process introduces errors, so minimise the number of steps you take.

Secondly, have you any statistics that validate your approach?

Have fun. JCS

 

[jlow]

I think having the perfect powder that gives that fill ratio would indeed be ideal but in today’s reloading component climate, you pretty much have to make do with what you have. Don’t have any argument in terms of problems with reloading steps but you do what you have to, if you have to.

Statistics to validate my approach, well yes. The funny thing was I had a 308 load that was working good in terms of accuracy but not so good in terms of MV SDEV. I replaced the Win brass I was using with LaPua which has a thicker wall and lower case volume and by the time I worked up to the same charge guess what? You guessed it. One instance is not absolute proof but it gets me thinking.

One should not be hugely surprised by this since this is in fact the real reason why a lot of people use a max or max plus charge. Most people think that it is because they are cowboys and just want to use a hot load but the unspoken reason I think is because of the above reason. Now, obviously it does not mean hotter is always better but assuming you have a sweet spot up there, if you can also find a accompanying load that is also a full/compress load you are likely golden.

 

[bigedp51]

I think having the perfect powder that gives that fill ratio would indeed be ideal but in today’s reloading component climate, you pretty much have to make do with what you have. Don’t have any argument in terms of problems with reloading steps but you do what you have to, if you have to.

Statistics to validate my approach, well yes. The funny thing was I had a 308 load that was working good in terms of accuracy but not so good in terms of MV SDEV. I replaced the Win brass I was using with LaPua which has a thicker wall and lower case volume and by the time I worked up to the same charge guess what? You guessed it. One instance is not absolute proof but it gets me thinking.

One should not be hugely surprised by this since this is in fact the real reason why a lot of people use a max or max plus charge. Most people think that it is because they are cowboys and just want to use a hot load but the unspoken reason I think is because of the above reason. Now, obviously it does not mean hotter is always better but assuming you have a sweet spot up there, if you can also find a accompanying load that is also a full/compress load you are likely golden.

Then think of the case as a cylinder in a gasoline engine, when you switched to a thicker case you changed the compression ratio. Now how many internal combustion engines inject Dacron fluff into the engine to improve combustion?

Your octane rating depends on if you use "High Test" double base powder or "Regular" a single base powder and the heat range of your spark plug. It could be your "fuel" doesn't like Russian spark plugs and your "mixture" is off.

 

[jlow]

So there are two parts to this discussion. Yes, when you use a thicker case, you change the case volume and that does affect combustion but at the same time, it also reduces the void volume which can also affect ignition consistency. The question is which is responsible for the more consistent MV SDEV. I don’t see it in your answer or mine for that matter, which is where experimentation comes in and why I am looking into Puff-Lon and asking the question.

The fact that you cannot inject Dacron fluff into an internal combustion engine has to do with the fact that it is a continuous cycle machine and not a single cycle, so that has nothing to do with the current discussion. So there is no logic or value in that argument.

 

[Outrider27]

The bottom line is that if you think it will help, try it out, but bear in mind that for those of us that have had positive results using Puff-lon or other dacron fillers, those results came from using them with loads we used chosen for good and substancial reasons, but which ended up filling a case 70% or less (mostly a lot less ). They don't seem to show any advantage in loads in a more normal fill range like 85% or more, though I suppose there is reason to experiment and see if the extra work of converting an 85%-95% load to a slightly compressed load using Puff-lon might improve accuracy, at least in some individual rifles. The calibers for which we have used it aren't usually shot with true boattail bullets, since they are mostly straight wall pistol cases with light loads of fast powders or the cavernous antique rifle cases like 45-70, 45-90, 50-90, 50-105, 50-110.

 

[bigedp51]

The fact that you cannot inject Dacron fluff into an internal combustion engine has to do with the fact that it is a continuous cycle machine and not a single cycle, so that has nothing to do with the current discussion. So there is no logic or value in that argument.

Contact David Tubb and ask him if he uses Dacron fluff and if there is any logic or value in using it.

Have you thought about nitrous oxide injection for your cases.
Less fluff and more huff.

 

[jlow]

Outrider27 – thanks. It is an experiment which means I don’t know if it will help but mostly asking to avoid problems that people may have already experienced. I do understand that it is normally used as you described and not the way I am thinking of testing. Thanks again.