I use .060" thick LDPE wads and have been plagued with bulged cases when compressing my powder. My cases are R-P and .40-65 with a straight neck. I am compressing almost .25". I have tried veggi wads of the same thickness and the budging has been greatly reduced but I have not shot a sufficient number of these reloads to have confidence that they are as accurate as the poly wads. I am also concerned that the veggi wads may stick more readilly to the base of the bullet and have been using a newspaper wad between the bullet and veggi wad as insurance. I am wondering if other have had my same experience with case bulging and have therefore switched to the veggi wads without any noticable decrease in accuracy or velocity. I would appreciate hearing your experiences.

I am using 70 grs of Swiss BP, 3Fg. I am getting the bulging when I compress the poly wad against the powder using a compression plug. The bulging is not occurring when I fire the case. The cases are not sticking in the chamber after firing and they do not come out bulged. I have to resize the case, when they bulge after compressing the powder, to get them to chamber. I hope this clears up any uncertainty.

Ten Pounds of powder in a 5 pound bag. Putting 70 Grains of powder in a case made for 65 is your problem.

40 Rod

Is there any difference between the diameter of the LDPE wads that you and Gunlaker are using?

Frank

My poly wads measure about .413 in dia. My bullets measure .410 and are a slip fit in my cases (my wads do require a push with a dowel to get started into the case mouth prior to compressing the powder). One thing I need to check is the diameter of my compression plug as I machined this down from a 45-cal one and went smaller than I intended. I am wondering if a relatively too-small plug might be causing the plastic wad material to flow out to the edges and swell the case when i compress the powder. This is all I can think that might be a potential problem right now. If I have another 45-cal plug I'll try machining it down to just where it fits the case mouth and compress some powder and see. 

Quote:

And I'll bet, your foul is harder than a woodpecker's nose using FFFg.  Smaller grains of BP burn hotter!

hepburnman wrote on Jun 23^rd, 2015 at 10:44am:

All right.......... another Hepburn shooter. Can't have too many Hepburns on the line.
Do you need 70gr of 3F Swiss? Are you shooting at 1000yd or something? ............ I shoot a Hepburn chambered in 40-65 and spot with several 40-65 shooters and compete against many others (BPCR & BPTR mid-range) and have yet run into anyone who loads as much as 70gr of 3F Swiss. Plus, the "common knowledge" with Swiss is that it shoots better (smaller SD) with little to no compression. Also have a long freebore (DanT designed reamer - may he RIP) and use a 413gr Money bullet with two reduced bands and find 64gr to be the max with 2F Swiss. Any more then that and the groups start growing. I use a fiber wad on the powder and a poly wad on top of that. Again, based on DanT's suggestion. Seems to be working as the rifle shoots better than I do. Am wondering if you have shot some ladder tests with 64/66/68/70gr of powder to see which groups the best? Obviously, YMMV.

Compress your powder with a compression plug then seat your poly-wad.  You will not get the bulge in the case.  I have found poly-wads to give superior accuracy as compared to vegi-wads.
OPS