filler test

[btroj]

Based upon previous discussions with other members here I decided to run a quick test on the use of fillers in my Marlin 45-70. I have never used a filler in this gun before and usually go with a load of 24 gr of 2400 with a 460420 plain base bullet. This load has worked very well for me over the years and is what I shoot the most in this rifle.

All these targets where shot in the order shown. The barrel was warmed with 5 shots first as I have seen erratic groups below 50 degrees from a cold barrel when using Carnuba Red. I fired all these groups in about 15 minutes and the barrel was not cleaned during the test. This loads has never given any, and I mean any, leading in this rifle. The bore is spotless after a single dry patch thru it.

I shot 4 targets using the same load. One load had a filler the other 3 targets were shot using no filler. The 3 targets were shot in the following manner. First group was fed single rounds into the chamber, no orientation of rifle prior to shooting. Second group was fired with each round being fed directly into the chamber and the barrel was pointed down and the gun was shook before bringing it level prior to each shot. This was to get the powder oriented as far from the primer as possible for each shot. the third group was fired with rounds fed from the magazine. As the rifle holds only 4 in the magazine I fired 4, 4, and 2. The rifle was not removed from the rest for this group.

http://castboolits.gunloads.com/imagehosting/thum_16434ea8684a17e44.jpg (http://castboolits.gunloads.com/vbimghost.php?do=displayimg&imgid=2507)

http://castboolits.gunloads.com/imagehosting/thum_16434ea8686792b8d.jpg (http://castboolits.gunloads.com/vbimghost.php?do=displayimg&imgid=2508)

http://castboolits.gunloads.com/imagehosting/thum_16434ea8687687fac.jpg (http://castboolits.gunloads.com/vbimghost.php?do=displayimg&imgid=2509)

All groups are shown in the same orientation as they were shot. All groups are 10 rounds at 100 yards from a bench. My scope was set to 6X as that is the highest magnification it allows.

Photo1 shows a 3 7/8" group. My chrono printer was giving me fits so I have only 6 velocity readings from this group. Average was 1380fps with an SD of 14.7.
This was the group with a filler.

Photo 2 shows a 2 3/4" group. The average for the 10 shots was 1257 fps with an SD of 18.5. this is the group where the powder was oriented away from the primer for each shot.

Photo 3 shows a 2 7/8" group. Average for the 10 shots was 1276 with an SD of 47.9. This group was fired with rounds fed thru the magazine.

It is obvious that the loads with a filler gave a higher and more uniform velocity. I was actually quite amazed at how much faster these were than the no filler loads.
The group fired with the rounds fed thru the magazine was the tightest outside of 2 fliers outside the main group. I think this was a factor as much of not removing my cheek from the gun for each shot which allows for a more uniform shooting position from shot to shot.

The overall results show me that a filler does allow more uniform velocity. The groups mean little to me as the difference is as much a factor of shooting style as the load. I need to redo the test but have all rounds fed thru the magazine. I didn't notice this flaw in my testing methodology until I was thinking about it on the drive home.

I will say that the no filler groups are very consistent with what this load and rifle have done over the years. I don't know that I will be going to using a filler any time soon with this load. The increase in velocity and more uniform velocities mean little to me if they don't change the point of impact at 100 yards. I don't hunt in an area where shots much over 100 yards are possible and I have shot 2 deer inside of 20 yards with this rifle.

Brad

[mpmarty]

Nice reporting and nice shooting Brad. I too omit fillers in my Marlin as I don't feel the small improvement available justifies the stories I've heard about ringed chambers etc. I don't want to be a statistic in this dispute.

[Jailer]

You never posted what and how much filler you were using.

I recently had a chance to test some loads with filler in my 45-70 and have found nearly identical results as you have. No more than 20FPS variance between shots when filler is used.

The best load was NOE 460-400 loaded with 28gr of 4198 and .7gr of dacron filler. These averaged 1320FPS and I had 3 shots through the same hole at 50 yards with open sights.

When I went to look at the target I was mad at first because I thought I threw the shots until I looked closely. One slightly oblong hole.

[btroj]

I used a bit of Dacron for a filler. Wasn't weighed, just enough to Lilly fill the airspace in the case.
I have never used anything else as a filler. Anything granular seems like too much work for me and I would probably spill it all over my bench.

[geargnasher]

You can throw many kinds of granular filler with a powder measure, making it easier to use than Dacron in some instances, but Dacron has a different effect on pressures than true fillers do. I like to think of Dacron as a powder locating device rather than a filler. Dacron, if used correctly (lofted and then compressed maybe 10-20% in volume), will locate the powder with only minimum effect of decreasing case volume.

You aren't likely to ring a chamber using Dacron alone unless you pack it down tight against the powder and leave airspace between the boolit base and filler. Same applies to any powder with any type of powder-locating wad that acts like a piston in the case. When the piston of a wad comes forward with the pressure front of burning powder behind it and slams into the boolit base, the boolit acts as a barrel restriction. The static inertia of the boolit will deflect the pressure front outward, like a soft lead boolit slamming into a steel plate, and the resulting pressure front can bulge or "ring" the chamber at that point. Once the mechanics of ringed chambers becomes clear, it's easy to understand how to avoid them, and gain the full benefits available to us with certain types of intert fillers.

One tip, posted here many times, and one that helps me a bunch, is to buy Dacron in rolled sheets that are intended for quilting projects. These sheets are uniform thickness, can be had in a variety of standard thicknesses (like 1/4", 3/8", etc.) and can be cut into squares with scissors. It's easy to determine weights of a given square by its size, so experiment and determine the size you need and cut them all the same size rather than weighing each individual piece. Much faster and much handier that way. The only disadvantage to this is it cuts many of the fibers short (especially on the corners), so it's slightly more difficult to "loft" and might take another tenth of a grain or two to make the same volume as "plucked" Dacron.

Gear

[Jailer]

Great explanation gear.

I only use enough to hold the powder in place as you have said. You can tell when you get it right, as the velocities even out and the accuracy increases. At least it has in my experience so far.

Then again, some powders respond to it some don't. I tried some with 40gr of 3031 and its didn't help at all.

[geargnasher]

It's a "krap shoot" as to whether or not any accuracy gained with the use of filler matters, or if it helps anything at all. We can often make educated guesses or just try it and see, although it's a dead-ringer that Dacron won't do much for improving loads in any cartridge with Unique as a powder. 2400, IME, is one of those powders that usually benefits from Dacron, so I'll recommend that most times. There are a lot of powders I haven't used with Dacron yet and don't have any useful input on those, but I use a lot of Dacron in reduced bottleneck rifle loads with cast boolits when I'm trying to get a little more velocity or lower pressure than I can normally get with Unique or Trail Boss.

Gear

[btroj]

I used the roll type Dacron. I cut a strip maybe an inch wide then tore off pieces of roily the same size. When pushed down into the powder they still were within 1/2 inch of the case mouth. The bullet base goes deeper than that so I know the Dacron was in contact with both powder and bullet.

I agree that Dacron is more of a "powder locator" than a true filler.

I was mostly surprised that the velocity was that much higher on average. I expected a bit but not that much.

Ultimately I am more interested in results on the target than results over the chronograph. These targets show me that a filler isn't a huge help with this specific load.

I also did reaffirm my beliefs that CR gives cold bore flier at temps below 50 or so. First shot from a cold barrel was over 5 inches from the rest of the first 5 I shot as barrel warmers.

[runfiverun]

filler also serves to make a case smaller.
you will always get higher velocities using a filler unless the load is reduced.
filler MUST touch both the powder and the boolits base preferrably with a slight amount of compression.

[1Shirt]

For what it is worth, I have always used filler with 2400 in 45-70 for my #1. I use about a 3/4" cut square of roll dacron pulled apart to make it fluffy. I have done it for years based upon Lyman listed recommendations in the past. Have always been satisfied with results and accuracy. I note that Lyman no longer lists it in load recommendations. Probably a lawyer factor now.
1Shirt!:coffee:

[Larry Gibson]

btroj

The use of the dacron filler does raise the psi and velocity. The reasons are as already explained. I note you used the same powder charge for all 3 groups with the PB'd bullet. That is fine as it demonstrated to you that the dacron filler does increase ignition efficiency and maintains it regardless of how the cartridge is fed into the chamber or the orientation of the rifle when shooting. That is one of the real benifits of the dacron filler.

Accuracy during normal bench type shooting at 50 and 100 yards may or may not be improved with the use of the dacron filler. However, it will improve accuracy with field shooting where the loaded rifle is carried at different angles, is shouldered differently from those cary positions and is fired at different angles. If shooting at larger targets like deer, pigs, etc. at close range there probably won't be much practilcal difference. However if shooting at smaller targets like squirrels or head shooting grouse then you'll quickly see a difference between loads with the dacron filler and those without, even at shorter ranges.

I would suggest you drop a couple grains of powder and work back up in 1/2 gr increments. You may find the same or better accuracy with the dacron filler at close to the same velocity as loads without. The 1250 - 1270 fps range may be the "sweet spot" for your rifle.

Also in answer to your PM question; Keep as consistent a position as possible (stock weld, elbow position on bench, foot position, return rifle to same position on bags after recloil and the same grip/should pressure) during each test string. Also trigger control is of the utmost importance. One last suggestion; control your breathing. I've watched too many shooter hold their breath too long. If you've not got the shot off in 6-8 seconds after you stop breathing then stop, take a few deep breaths and try again. You'ld be surprised at how fast the eyes are affected and the aim is bad, even with a scope, if the breath is held too long.

Larry Gibson

[btroj]

I plan, weather permitting, to rerun parts of the test in the next week or so.
All will be fed thru the magazine eliminating that source of potential error.
What I found interesting was that the muzzle pointed down group was the same size as the one fed thru the magazine. Feeding the round from the magazine jiggles the case around enough to make the powder location pretty random.

Until I can show a difference in accuracy I will probably continue ue to use no filler with this load. It shoots very well offhand for me fed thru the magazine. This is another situation that pretty randomly positions the powder.

The extra velocity, and the amou t of increase, was the most amazing thing to me. I expected maybe 50 fps but not in the 125 to 150 fps range. For the velocity of the load that is pretty significant- roughly 10 percent!

I will let you know what I find with the retest. It will also be with MMl rarer than CR. the CR just doesn't do as well for me once it gets colder and sadly, it is colder now in eastern NE. We are getting wet snow and wind right now.

[pmer]

This thread is timely for me. I got interested in fillers because of my playing around with a 458 Lott and the 46-500L boolit.

I wanted to try a slower powder because 5744 was making the boolit skid. I saw that J bullet loads had a fairly narrow range of charge weights and I had some of these powders on hand. I didn't have any COW and decided to blend up some oatmeal and use it in my straight walled cases.

I tried 52.0 VV N540 and 2.8 CCs of the oatmeal and was getting almost 1750 FPS. No shinny heads and primers looked happy. The oatmeal didn't quite fill the case and was compressed by the boolit. Starting load was 76.0 grains (I think).

The leading moved from the start of the bore to the end of the bore I think because of my lube and velocity? The lube was RCBS pistol with streaks of LBT soft in it.

I do have some COW now. I'm trying to make the case smaller so these fillers are better in my case, I think? But it is wierd putting something other than gun powder in the cases.

[crabo]

Great explanation gear.

Then again, some powders respond to it some don't. I tried some with 40gr of 3031 and its didn't help at all.
It made a difference in my guide gun with this load. It increased velocity and shrunk group sizes and velocity deviations. I think Gear is right, It is a krap shoot, depending on gun and components.

[Larry Gibson]

I have to disagree, it is not a "krap shoot". Btroj has changed something with the dacron filler. That gave more consistent ignition but at a higher psi and velocity. That's why it is necessary to reduce the load and work back up. It could very well be that that bullet of that alloy just like the velcoity in the 1250 - 1270 fps range and not higher. Some cal it the "sweet spot" and some call it the "accuracy load" but none the less when you cahnge something in a load you need to work back up for best results. It's what we all say in other matters and it's what we should look at in this matter. All of my dacron filler loads, regardless of cartridge, use less powder to achieve the same level of velocity and accuracy. I would really expect anything different here.

Larry Gibson

[Jailer]

Good point Larry.

I haven't had good results with 3031 with or without filler, but I haven't tested as extensively as I have with 4198. I just happened to stumble on something that worked well with 4198 so that's what I've been concentrating on.

Maybe after hunting season is over I'll go back to the drawing board with 3031. Sooo many people seem to have such good luck with this powder in 45-70 that I can't help but think that I just haven't got it right yet.

Besides it will give me a reason to do some more shooting with this gun once hunting season is over. :D

[geargnasher]

Not a "krap shoot", but an educated guess. If you're like me, you're still experimenting to make it a little more educated and less guess.

Gear

[btroj]

Not a "krap shoot", but an educated guess. If you're like me, you're still experimenting to make it a little more educated and less guess.

Gear

Exactly. And that is why I am continuing to test.
I may need to put some of this off til next year, too cold these days.
Right now I need to get my hunting load together and that is more about lube than filler right now.

brad

[caseyboy]

Not to hijack this thread, but just a little additional info. I was up at the range shooting my 7mm-08 with GCed Lee 130s. A fellow a few benches over pulled out his chrono to set up. I asked him if I could put a few through to satisfy my curiosity. The three shoots at about 6yds from the muzzle read 1766, 1765 and 1766. A one fps spread between three shots. Not conclusive by any stretch, but very encouraging. The charge I was using was 15.0grains of Alliant2400. Keeping the powder all together up against the primer seems to keep ingition very consistent. I also am seeing nice groups on the 100yd and 200yd targets.:bigsmyl2:

[geargnasher]

You were using filler of some sort this time I presume?

Gear

[crabo]

I have to disagree, it is not a "krap shoot". Btroj has changed something with the dacron filler. That gave more consistent ignition but at a higher psi and velocity. That's why it is necessary to reduce the load and work back up. It could very well be that that bullet of that alloy just like the velcoity in the 1250 - 1270 fps range and not higher. Some cal it the "sweet spot" and some call it the "accuracy load" but none the less when you cahnge something in a load you need to work back up for best results. It's what we all say in other matters and it's what we should look at in this matter. All of my dacron filler loads, regardless of cartridge, use less powder to achieve the same level of velocity and accuracy. I would really expect anything different here.

Larry Gibson

I used "krap shoot" meaning it may or may not work for you. It will take testing to find out. Simply adding filler to a particular load, is not a guarantee that it will improve. That was the point I was making.

[caseyboy]

Sorry Gear, yes I was using a 1.0grain tuft of Dacron. Enough to take up the space from the powder to the boolit base.

[btroj]

I did some more testing today. Weather was such that the groups don't really show anything.

I was interested to see that the MML lube did seem to cut down on the first shot flyer problem. Once the barrel warmed up it didnt seem to shoot quite as good as the CR but only time can really tell. 25 to 30 degrees is not the time to shoot small groups.

Did see something odd. With CR the no fill shots averaged 1276 with the fill group at 1380. A difference of almost 100 fps. With the MML the fill group averaged 1368 but the no fill was up to 1335. A difference of only 33 fps.

Seemed odd that the no fill velocity went up but the fill velocity was actually a bit lower. None of this means alot as the chronograph is not that precise and the differences are pretty small but it still struck me as odd.

I did pick quite a bit of filler up off the ground after firing. The dacron is blackened a bit but I see no signs of any melting. Upon firing it almost looks like it is snowing dacron! Mt father in law tells me I am using way too much, I will have to weigh the amount I was using and see how much it was.

For those that use dacron- how much is too much? I have been using enough to fill the space between the powder and the bullet base. It is not compressed by any means but it also is not "fluffy" once the bullet is seated. I am using the roll batting type and it is a piece about 1 inch square. Other than being wasteful is there any harm in using more rather than less?

Brad

[Larry Gibson]

btroj

The variations in velocity may be more the simple variation one gets when testing the same load in different test strings. A comprehensive test with a good chronograph of three 10 shot strings each would give an answer with almost complete "assurance".

I've tested dacron filler in the 45-70 using 25 gr 5744 under a 413 gr cast bullet with no filler, 3/4 gr dacron filler, 1 gr dacron filler, 1.5 gr dacron filler, 2 gr dacron filler and 2.5 gr dacron filler. The 3/4 - 1.5 gr gave essentially the same accuracy, 1222 fps and 25,000 psi. The 2 & 2.5 gr (quite compressed) dacron filler loads showed a small increase in velocity and psi with the 2.5 gr load running 1240 fps at 26,700 psi. Accuracy was also not quite as good. The results with the 45-70 are atypical of other similar tests in other cartridges.

My recommendation for the use of a dacron filler in any cartridge has been, and still is, to use just enough to fill the space with 'fluffy" dacron. I've not found any need to weight the dacron fillers to be precise and testing has provided no evidence an exact weight of dacron improves velocity or psi ES/SDs. That's why when I cut up the batting sheets of dacron I eye ball the chunk cuts using weighed chunks as examples. This works quite well for me over a number of years and thousands of such round.

Larry Gibson

[btroj]

All the velocities I listed were averages for a 10 shot string. I just don't like usi 1 shot or even 5 shots to get a "velocity" for a load. I have seen too much variation over the years to trust a small sample. I know that SE means little on a small sample but all three loads todays had SD numbers in the 23 to 28 range. I thought it was interesting that they were so similar in SD for 10 shot strings. Not a big deal but odd in my mind.

I will probably cut up some batting for a most consistent fill. I just tore about equal pieces off a 1 inch or so wide strip. Itis reassuring to know the someone has tested larger Amos with no I'll effects or excessive pressures.

I will or likely have to wait for spring to do much ore testing. Deer season and bad weather are going to hamper any efforts this month.

This has peaked my interest however.

[geargnasher]

Larry, you give excellent and well-tested advice as usual, thank you for simplifying the testing for some of us, providing some example baselines, and helping us to save components for more useful, pinpoint testing. After reading your experiences with fillers since I joined this forum I've learned a lot, and I've never bothered to use more than about 125% Dacron AFTER it was "fluffed up", (often less) and it's always given me very good results if the filler was truly "indicated" by the powder, case, and boolit choice.

Gear