Charge weight difference when suppressed?

[PinesAndProjectiles]

I am shooting a 6.5x47 and 130 grain Berger Hybrids. Without the can, I can push them with 37.5 grains of Varget, without any pressure signs.

When I run the can, I get ejector marks on every piece of brass, even with 36.9 grains of Varget.

For those that run a can, what kind of differences are you seeing in charge weights with a can vs without?

I am running a Rugged Surge at the full length (9 inches) on a 22 inch Shilen and a Savage action.


Also, I was fire forming some brass last weekend and started with a charge weight of 34 grains of Re15, which is middle of the road for the Berger published data (whcih tends to be very low when compared to everything I read here). I fired two rounds with the can and both had ejector marks. I then stopped shooting them. I wouldn't think a charge weight of 34 grains would yield pressure signs.

Any help would be appreciated.


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[spife7980]

I figure that this is a bolt based off of the cartridge but if it's a semi then I think the answer would be easy, an adjustable gas block or another way to slow the gas down a bit.

Ive never noticed that issue with my omega and three suppressed rifles that I reload for. I try to not keep my foot in the throttle however so that limits its usefulness.

i assume you're using lapis brass and not something soft? How close is your 37.5 from too much pressure without the can attached?

 

[sierracharlie338]

I have seen the same thing with my old 308 shooting 175s and Norma brass. Fine without the can but with it (AAC Cyclone) I started getting marks on the brass. I had a lot of other head scratching issues with the rifle so GAP is giving it a make-over Cant Wait!!

 

[PinesAndProjectiles]

Sorry, yes this is for a bolt gun. 37.5 is getting close as far as pressure without the can.



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[supercorndogs]

Varget seems a little on the fast side, for your case capacity, and bullet size. Maybe you are getting a pretty good pressure spike. I have had several loads I had to back off once I put a suppressor on. Some I had to back off to shoot long string suppressed.

 

[earthquake]

I backed off about 1.5 gr. Was running 42.9 H4350 and flattened primers when I put the can on it. 140's

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[PinesAndProjectiles]

To me, I wouldn't say that my primers are flat. They look to still have a rounded edge on them. Here's a few pictures.


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In this picture, the arrows are pointing at ejector marks.

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[jwood1284]

I get slight ejector marks on all my Lapua brass (6.5x47, 130gr OTM, 39.4 RE17), but they are very feint and there doesn't appear to be any brass flowing. Your ejector marks don't appear to be any worse than mine, but your primers show some cratering. Do you get heavy bolt lift with the can on?

 

[PinesAndProjectiles]

Jwood, only occasionally. I load 5 rounds of each charge weight and i may have one of the five that seem to be sticky on the bolt lift.

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[tylerw02]

I used to run a similar load and eventually came to the conclusion that Varget was too fast for the cartridge, especially suppressed. I switched to H4350 and the problems went away.

Typically, I work up my load with the suppressor if I intend to use the suppressor.


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[Conrad]

If you have a sticky bolt at times you should back off for a variety of obvious reasons but also running a sticky bolt just isn't that much fun. I was getting a little sticky with 40.3 gr H4350 and 105 Hybrid in 6xc with Ultra-7. I dropped down to 40gr and no issues. hBN coated bullets FWIW.