How do these primers look to you?

[uncle-buck]

Developing a load in .243 Win. using Lapua cases, WLR primers, Sierra 100 gr. Pro Hunter bullets seated with a .010" jump, and IMR-4350 powder loaded in half grain increments from 38.0 to 41.0 grains.

Best results, so far, have been obtained with 39.5 gr. of powder (shown below in the center column).

Have not chrony'd them yet and have had no problem lifting the bolt, but am not sure if the primers look like they are supposed to look.

Thanks for any feedback.

 

[Comrade Terry]

Developing a load in .243 Win. using Lapua cases, WLR primers, Sierra 100 gr. Pro Hunter bullets seated with a .010" jump, and IMR-4350 powder loaded in half grain increments from 38.0 to 41.0 grains.

Best results, so far, have been obtained with 39.5 gr. of powder (shown below in the center column).

Have not chrony'd them yet and have had no problem lifting the bolt, but am not sure if the primers look like they are supposed to look.

Thanks for any feedback.

Can't see the image, Uncle Buck.

 

[majohnson]

With a micrometer measure the base and then about a 1/4" above if there more then .0005 difference it to hot. Primers do not always tell the story.

 

[6MMsteve]

look backed out to me, is that what you think? little flat

 

[TheOtherZilla]

Just from looking they seem OK. According to the IMR 243 load data for 100 grain bullet you are well under max With the 39.5 load. Max is 42 grains of IMR 4350.. My Sierra book says 41.7 is max for 100 Sierra and IMR 4350..

 

[RonAKA]

The middle row, second from the right side, looks like it is getting up there for pressure, but I would still accept if it gave good accuracy. You should be able to get the same velocity with less temperature sensitivity by moving to H4350.

 

[Iowa Fox]

look backed out to me, is that what you think? little flat

Look a little backed out to me also. What is your measured headspace on a loaded round before you fire it?

 

[timeout]

Primers look fine. As others have said they are not the only or even necessarily the best indicator of pressure.

 

[uncle-buck]

Appreciate the comments, gents. Do not know the head space and will have it checked. Will also test the H4350 and see how it performs. It's a hunting rifle, so it doesn't need to approach perfection, but I do like accuracy. The Sierra manual lists tested loads with Federal cases and believe the Lapua cases may develop more pressure for the same powder charges. Thanks again

 

[M-61]

Primers look fine. As others have said they are not the only or even necessarily the best indicator of pressure.

+1.........notice anything with the bolt being harder to open?

 

[uncle-buck]

Haven't noticed the bolt being harder to open. Simply wanted to get some experienced opinions on the way the primers look. Have read that running hot loads leads to more rapid throat erosion. The rifle seems to really like the load mentioned in my original post.

 

[majohnson]

Here's a piece on pressure

http://www.hodgdonreloading.com/rel...-trick-monitoring-pressure-your-rifle-reloads

 

[RonAKA]

Haven't noticed the bolt being harder to open. Simply wanted to get some experienced opinions on the way the primers look. Have read that running hot loads leads to more rapid throat erosion. The rifle seems to really like the load mentioned in my original post.

That 39.5 load is well within normal load limits for the .243. It would be nothing to worry about. If your priority is barrel life then I suggest you download the barrel life calculator spreadsheet, and try some different powders to see what estimated life you get. Some powders have significantly less heat potential than others.

 

[WSnyder]

With a micrometer measure the base and then about a 1/4" above if there more then .0005 difference it to hot. Primers do not always tell the story.

Measuring at the .250" line at best might tell you a little about the chamber diameter at that point but not pressure. I see this come up a lot lately and many need to step back and read about the proper procedure and the pitfalls of the procedure even when done properly.

http://www.hodgdonreloading.com/rel...-trick-monitoring-pressure-your-rifle-reloads

http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/19115/Measuring_case_head_expansion

http://lmgtfy.com/?q=Measuring+case+head+expansion

 

[yotehater]

I thought they looked a little backed out too with an off center firing pin strike.