Your experience with Dacron filler?

[bigedp51]

jlow

Below is Quickload data using Sierra load information and their max load of Varget of 41.7, Hodgdon's data lists 45.0 as a max compressed load. I have a love hate relationship with Quickload because some of data it spits out shows extreme high and low pressures and I'm not sure if I'm missing some other input. As you can see below the 45.0 grain Hodgdons load is 62,011 psi and over max. The "fill %" is loading density and I thought you might be interested.


Cartridge : .308 Win.
Bullet : .308, 175, Sierra HPBT MatchK 2275
Useable Case Capaci: 47.981 grain H2O = 3.115 cm³
Cartridge O.A.L. L6: 2.800 inch = 71.12 mm
Barrel Length : 26.0 inch = 660.4 mm
Powder : Hodgdon VARGET

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 78 33.36 2097 1709 27307 5043 90.2 1.711
-18.0 80 34.19 2145 1787 28973 5196 91.2 1.670
-16.0 82 35.03 2192 1867 30737 5347 92.2 1.630
-14.0 84 35.86 2240 1949 32604 5493 93.1 1.591
-12.0 86 36.70 2287 2033 34583 5635 94.0 1.554
-10.0 88 37.53 2334 2118 36681 5772 94.8 1.517
-08.0 90 38.36 2382 2204 38904 5904 95.6 1.478
-06.0 92 39.20 2429 2292 41253 6030 96.3 1.440
-04.0 94 40.03 2476 2381 43725 6151 97.0 1.403
-02.0 96 40.87 2522 2472 46336 6266 97.5 1.367
+00.0 97 41.70 2569 2564 49106 6374 98.1 1.333
+02.0 99 42.53 2615 2658 52045 6475 98.5 1.300 ! Near Maximum !
+04.0 101 43.37 2661 2753 55167 6569 98.9 1.267 ! Near Maximum !
+06.0 103 44.20 2707 2848 58483 6655 99.3 1.236 ! Near Maximum !
+08.0 105 45.04 2753 2945 62011 6734 99.5 1.206 !DANGEROUS LOAD-DO NOT USE!
+10.0 107 45.87 2799 3044 65765 6804 99.7 1.177 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 97 41.70 2675 2781 57670 6263 100.0 1.248 ! Near Maximum !
Data for burning rate decreased by 10% relative to nominal value:
-Ba 97 41.70 2426 2288 40731 6200 92.5 1.443

 

[Rbreb13]

Not sure if its Dacron but I regularly use some pillow stuffing I bought a Walmart in my 45-120 loads. Modern smokeless powders don't even come close to filling the case.

 

[jlow]

bigedp51 - Thanks – some very interesting data – thanks for posting.

The first thing that surprise me about this is Quickload is showing data down to 33.36 grains for the Varget/175 combo. Just looking at the table from Hodgdon’s website, their recommended “starting load” is 42 grains with 45 being the max.

The other thing which is a surprise is at 42 grain, Quickload is showing around 98% filled which is interesting. I am currently using 44.1 grain which it says is around 103% filled which may be correct.

Now all this is based on a “usable case capacity of 3.115 cc – I wonder what case this reflects? I am using Lapua which I know for example has significantly lower case volume than Win brass? Lots of interesting questions.

Rbreb13 – pillow stuffing may in fact be Dacron.

 

[bigedp51]

jlow

The internal capacity of the case must be entered for Quickload, the figures above are for a case capacity of 56 grains of H2O. For Quickload to be accurate I need at the minimum the case weight of your Lapua brass or even better how much H2O your cases holds. The Lapua case weights below show H2O data.

NOTE: Case capacity
If I enter 54.4 grains of H2O and 44.1 grains of Varget the chamber pressure is 63,063 psi.
If I enter 55.84 grains of H2O and 44.1 grains of Varget the chamber pressure is 58,933 psi.

Below are capacities from the websites linked below the data.

LAPUA runs an average of 54.4gr
http://www.6mmbr.com/308Win.html

Here are some Lapua .308 brass weights and how much they can hold. These are all once fired and still with the primer I will do some new one when I get a chance.
Brass GR Amount of H2O held by case in GR
177.2 held 56.3
176.3 held 56
176.5 held 55.8
176.6 held 56.1
177.2 held 55.1
177.2 held 55.6
176.4 held 55.9
177.1 held 55.8
177.9 held 55.9
177.5 held 56
So average is 55.84

Lapua Brass Trim Length- 2.005 can hold 51.2 grains of Varget
Winchester Brass Trim Length- 2.005 can hold 52.5 grains of Varget[/color

http://www.700rifle.com/forums/viewtopic.php?id=908

Now all this is based on a “usable case capacity of 3.115 cc – I wonder what case this reflects? I am using Lapua which I know for example has significantly lower case volume than Win brass?

56.0 grains of H2O capacity = Useable Case Capacity: 47.981 grain H2O = 3.115 cm³

55.84 grains of H2O capacity = Useable Case Capacity: 47.814 grain H2O = 3.104 cm³

54.4 grains of H2O capacity = Useable Case Capacity: 46.374 grain H2O = 3.011 cm³

 

[jlow]

Hi bigedp51,

Thank you again for your reply and apologies for the slow response – spend the last 8 hours out at our club’s range putting in a new bay so its been a long day.

Thanks for the explaination. Right about entering the right internal capacity for the brass I am using. As mentioned in the OP, I am using Lapua brass and although I have not measure their internal volume, I have good information on their weight which is 176.93 grains (30 cases). So very close to what you have found for weight of LaPua brass. The chamber pressure of 63,063 psi would seem to be correct as mentioned in my OP I was seeing ejector swipes on the brass.

Seems like quite useful software and I will have to look into Quickload!

 

[bigedp51]

jlow

If I had to it over again I would have spent the money on a better trigger or more reload gear. I spent a good deal of time entering the data from reloading manuals into quickload and the pressures and velocities do NOT match much of the manuals data.

For Quickload to work accurately you need to input more information than I'm able to give it. On the same page in the reloading manuals you may get close to the manual with one load, but another load will not even be close to the manual.

I did without Quickload for 46 years of reloading and its nothing more than a fancy version of the Powley Computer which I also have gathering dust. There is a reason WHY the different reloading manuals data varies and Quickload data varies even more.

Your brass is giving you better information than Quickload guesstimates will.

 

[jlow]

Thanks bigedp51 – your frank input is much apparciated.