how changing components affects MV and PSI

Reloader · Post by **Reloader** » July 24th, 2014, 4:55 pm

The JHs really work well with the TPS John. The CSD does well in them too.

Hal,

I think it makes a huge difference with the combustion chamber. Take lead wads for instance, the piston stem on some compresses very easily. I took some of the red AA12R wads and compressed the piston just a little more than the legs remaining straight and psi on the PT shot up something like 4k! I also took a load that was a given MV with BPI gas sub bases stacked and replaced with a cushion piston. The MV fell around 600fps!

I know a guy that built his 3.5" TSS loads using the same thinking, but built the charge up until the MV came back to what he desired. Sent them to the lab and they checked out fine even with the much larger charge. The combustion chamber size at ignition makes a difference.

hawglips · Post by **hawglips** » July 24th, 2014, 5:41 pm

Reloader wrote: I think it makes a huge difference with the combustion chamber. Take lead wads for instance, the piston stem on some compresses very easily. I took some of the red AA12R wads and compressed the piston just a little more than the legs remaining straight and psi on the PT shot up something like 4k! I also took a load that was a given MV with BPI gas sub bases stacked and replaced with a cushion piston. The MV fell around 600fps!

Whenever I am working on a load I always count on more cushioning decreasing MV and PSI with TSS. I've had guys who are only familiar with lead tell me I'm an idiot for thinking that cushion decreases MV and PSI. But it's a reality that has to be considered with hard shot.

Johndoe · Post by **Johndoe** » July 24th, 2014, 6:38 pm

Reloader wrote:The JHs really work well with the TPS John. The CSD does well in them too.

Hal,

I think it makes a huge difference with the combustion chamber. Take lead wads for instance, the piston stem on some compresses very easily. I took some of the red AA12R wads and compressed the piston just a little more than the legs remaining straight and psi on the PT shot up something like 4k! I also took a load that was a given MV with BPI gas sub bases stacked and replaced with a cushion piston. The MV fell around 600fps!

I know a guy that built his 3.5" TSS loads using the same thinking, but built the charge up until the MV came back to what he desired. Sent them to the lab and they checked out fine even with the much larger charge. The combustion chamber size at ignition makes a difference.

Yep I have played with the LBC just don't know if anyone had done any TSS with CLBC.
Fewer corks and felts needed.

Spuriosity · Post by **Spuriosity** » July 24th, 2014, 7:57 pm

Johndoe wrote:Yep I have played with the LBC just don't know if anyone had done any TSS with CLBC.
Fewer corks and felts needed.

John,

The CLBCs work great with TSS. My 12 ga 1.625 oz load uses them with LS powder with safe pressures (1097 fps/ 9552 psi). As you know, LS is a fairly fast burning powder compared to Steel, 2400, LG, 296, etc. The cushioned wad makes it possible. Good patterns too (250/280 with 372 count 9s).

hawglips · Post by **hawglips** » July 25th, 2014, 7:03 am

Johndoe wrote:Yep I have played with the LBC just don't know if anyone had done any TSS with CLBC.
Fewer corks and felts needed.

I've worked with the CLBC wad, but found it doesn't seem to pattern as well for me with four full slits as some of the other wads do. The last couple years I've been coming up with some loads for the B&P cushioned wads (TUWSBL/CSD series) in order to eliminate the need for filler/cushion. The 24 is just right for 1-3/4 oz, the 28 for 2 oz and the 32 for (if I recall correctly) 2-1/4 oz. They pattern well and manage chamber pressures well also. I like them for the 12 gauge - but not so much for the 20. The only word of caution with the cushioned wads with no filler is, that during setback there is nothing inside the shot cup to collapse and so you can't fill the wads up as full as you can when there is cushion inside the shotcup under the shot.

Reloader · Post by **Reloader** » July 25th, 2014, 8:01 pm

I agree, the 20ga csd/B&P are a touch thin and get eaten up w/o Mylar.

hawglips · Post by **hawglips** » July 26th, 2014, 5:58 pm

I gave up on the twenty gauge CSD with heavy payloads of TSS when it consistently tore up for me even with Mylar. But it does well when combined with a second wad. Kyle Smiths 1 oz load with the mag 28 inside as an example. I also like to use it as an inner layer in a 12 gauge load.

Reloader · Post by **Reloader** » July 26th, 2014, 10:03 pm

Yep, it does work well that way. My kid load is a csd with a stack of felt and a AA 28ga cup with piston removed. Pushing 1oz to only 1080 is a pussy cat for recoil.

REHH · Post by **REHH** » September 4th, 2014, 9:35 am

Interesting thread Hal

01Foreman400 · Post by **01Foreman400** » March 19th, 2015, 9:14 am

Any chance of a 2.25 oz. 3" Federal substitute load?

hawglips · Post by **hawglips** » March 19th, 2015, 5:17 pm

01Foreman400 wrote:Any chance of a 2.25 oz. 3" Federal substitute load?

On the to-do list.

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