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Fire Forming 7.62X39 brass to 6.5 Grendel


Dirty Hairy
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Anybody out there done this? If so how is it done? Never done any fire forming on any brass.

 

Here is a cut and paste from LR1955 from the 65Grendel site. It goes over the basics very well.

 

LR1955's 7.62x39 to Grendel resizing process

 

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:flea:

Lay out X number of 7.62X39 brass on a towel. Spray lightly with Dillon spray lube. Run 5 pieces of brass through through a Grendel sizing die. Take those 5 pieces of the sized brass and run them through the chamber to ensure they are easy to chamber and easy to extract (thus showing they were sized down enough). Given they chamber and extract easily, size down the rest of the brass as your die is set properly. Once done, take five of the sized down pieces of brass and measure them to ensure the length is within specs for Grendel brass. So far I haven't found WW or IMI 7.62X39 brass to be longer than maximum for the Grendel so I haven't had to trim virgin brass. If one does find that the brass is too long, one can trim them. When done, clean up the necks using any of the neck champhering tools available, load, and shoot.

 

The first loading with either the AA / Lapua or 7.62 X 39 brass will blow each of the brass types out, thus allowing more powder on reloading so the initial powder charges will be less than what one may use there after. Any virgin brass will be blown out on the first firing as virgin brass is deliberately made undersized so it can expand to fill chambers made with different tolerances

:m4:

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I would add pick a lighter-moderate load for the first firing of these to get the fire form (basically just stay away from max loadings.) Some people load really light and some people load mid range and actually shoot for groups. It's up to you. I like using Speer Hot Cores as they are cheap and a mid range load of TAC and run my practical shooting drills. That way I get practice and work the brass at the same time. HTH!

 

 

Medic...out!

Edited by KillerMedic
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Hey Medic,

Thanks a "load" for the info. That Grendel brass is scarce and very highly thought of. I've wondered if the 7.62X39 could be resized for the G. Now I can build up my stash of that too. I've got about 500 loaded with mostly feeebie AA and Lapua thanks to my bud who's a test fire tech at Sabre Defence. He's gotten kinda possessive with it since he got his own dies but I'm more than grateful for what I've already gotten.

 

 

Thanks again,

Dirty

 

 

Here is a cut and paste from LR1955 from the 65Grendel site. It goes over the basics very well.

 

LR1955's 7.62x39 to Grendel resizing process

 

--------------------------------------------------------------------------------

:flea:

Lay out X number of 7.62X39 brass on a towel. Spray lightly with Dillon spray lube. Run 5 pieces of brass through through a Grendel sizing die. Take those 5 pieces of the sized brass and run them through the chamber to ensure they are easy to chamber and easy to extract (thus showing they were sized down enough). Given they chamber and extract easily, size down the rest of the brass as your die is set properly. Once done, take five of the sized down pieces of brass and measure them to ensure the length is within specs for Grendel brass. So far I haven't found WW or IMI 7.62X39 brass to be longer than maximum for the Grendel so I haven't had to trim virgin brass. If one does find that the brass is too long, one can trim them. When done, clean up the necks using any of the neck champhering tools available, load, and shoot.

 

The first loading with either the AA / Lapua or 7.62 X 39 brass will blow each of the brass types out, thus allowing more powder on reloading so the initial powder charges will be less than what one may use there after. Any virgin brass will be blown out on the first firing as virgin brass is deliberately made undersized so it can expand to fill chambers made with different tolerances

:m4:

---------------------------------------------------------------------------------

 

I would add pick a lighter-moderate load for the first firing of these to get the fire form (basically just stay away from max loadings.) Some people load really light and some people load mid range and actually shoot for groups. It's up to you. I like using Speer Hot Cores as they are cheap and a mid range load of TAC and run my practical shooting drills. That way I get practice and work the brass at the same time. HTH!

 

 

Medic...out!

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Hey Dirty,

 

No problem, glad to help. If you have not already seen it posted, Wideners has the IMI 7.62x39 brass in stock at a good price. http://www.wideners.com/itemdetail.cfm?item_id=1074 The large primer pockets had been rumored to not hold pressure as well as small pockets. But recent posts on some tests, and some testing I did over a year ago and posted on 65Grendel.com, showed higher velocity from like loadings on the large pocket brass with no signs of overpressure. Next step is to test how many reloadings this remains true.

 

 

Medic...out!

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Medic,

 

I have several wolf 6.5G brass (large primera) that apparently blew the primers out on first firing. I resized them and tried priming with RCBS hand primer, no risistnace, went to recycle bin. Most of the wolf brass I have held fine but I prefer the AA or Lapua with small primer pocket. They seem to be more consistant than the wolf. I saw your original post on the IMI brass before I posted requesting how to info. Thanks on both counts.

 

Load safe/shoot straight,

Dirty

 

 

 

Hey Dirty,

 

No problem, glad to help. If you have not already seen it posted, Wideners has the IMI 7.62x39 brass in stock at a good price. http://www.wideners.com/itemdetail.cfm?item_id=1074 The large primer pockets had been rumored to not hold pressure as well as small pockets. But recent posts on some tests, and some testing I did over a year ago and posted on 65Grendel.com, showed higher velocity from like loadings on the large pocket brass with no signs of overpressure. Next step is to test how many reloadings this remains true.

 

 

Medic...out!

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Yeah, you can't count the Wolf in the running of the small/large primer choice. It is just not of the same quality as the commercially available brass. It has been declared too soft and inconsistent and is known for popping primers and not holding them well on reloading. I have a batch of Wolf that has done well on 2x reloadings so far but I am not expecting more than 1 or 2 more from it. I also have 400 AA/Lapua brass I keep for my LR/accuracy rounds.

 

 

Medic...out!

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Yeah, you can't count the Wolf in the running of the small/large primer choice. It is just not of the same quality as the commercially available brass. It has been declared too soft and inconsistent and is known for popping primers and not holding them well on reloading. I have a batch of Wolf that has done well on 2x reloadings so far but I am not expecting more than 1 or 2 more from it. I also have 400 AA/Lapua brass I keep for my LR/accuracy rounds.

 

 

Medic...out!

Good post about fireforming...however read more at 6.5 Grendel about using 7.62x39 brass. The Grendel bolt face has slightly different dimensions. Don't just jump on it before researching. Fireforming has created alot of wildcat cartridges, one comes to mind is the Ackley. Blown out shoulders, increased case capacity, and a valocity gain over factory cartridges. The 65 G was originally created from the .220 Russian cartridge. I have picked up some of them at the range thinking they were my 6.5G, only getting home and sorting brass and finding they were not.

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