300 WSM reamer spec?

[Fordnutter]

Hi Guys,
Planning a 300 WSM precision rifle build for long range varminting & F Class competition. I'm going to order a Reamer from PTG but wanted to check on recommendations of reamer specification. I have a quantity of Norma brass on hand & a Redding competition Neck die set already. I don't mind neck turning brass so were thinking a .337 neck, minimum spec chamber & zero free bore so with a seperate throater we'll just throat accordingly..... standard SAAMi leade angle???

Any suggestions are much appreciated.

 

[Steve Blair]

Leade angle should be 1½°. My reamer is a PT&G .300 WSM Match with Ø.337" neck and .280" freebore. The feebore is solely for Berger 230 grain Hybrids.

 

[ThunderDownUnder]

Leade angle should be 1½°. My reamer is a PT&G .300 WSM Match with Ø.337" neck and .280" freebore. The feebore is solely for Berger 230 grain Hybrids.

Steve, do you have a print of this reamer as I'm in the process of getting one from PT&G but they are a little busy at the moment and I have not been able to get hold of the "Match" reamer print.

Ian

 

[Steve Blair]

Steve, do you have a print of this reamer as I'm in the process of getting one from PT&G but they are a little busy at the moment and I have not been able to get hold of the "Match" reamer print.

Ian

[br]
I just got back from Phoenix and can't find it but will come up with it today, scan and post it. My reamer is intended for Norma brass.

 

[ThunderDownUnder]

Steve, I have Nosler custom brass which is made by Norma and prepped by Nosler. Thanks for looking up the reamer print for me! Does your 300WM group well with the 230 grainers and the PT&G Match chamber?

Ian

 

[Steve Blair]

Sadly, the build is still underway and not finished (started February). But, I shot with Denny Welker this weekend in Phoenix and he reports that his .300 WSM is shooting very well with 230 Hybrids. They shoot great in .308 Win with a 10" twist, grouping under 1/4 MOA. If I could just learn how to manage them on the bipod, it would be a winning load.

 

[Steve Blair]

Here is the reamer print.

 

[ThunderDownUnder]

Here is the reamer print.

Thanks Steve! That reamer provides a tight neck but the rest of the dimensions are pretty standard. Its not a minimum spec saami chamber, look here for saami spec; http://www.saami.org/PubResources/CC_Drawings/Rifle/300%20Winchester%20Magnum.pdf
I am after a no neck turn, minimum spec chamber which is probably the exact opposite of your Match chamber. I am hoping a min spec chamber will restrict case stretch and with headspacing off the shoulder the brass should last many reloadings. Thats the plan and the reality could be a different story but until I get a chamber cut its all theory until proven.

Ian

 

[Steve Blair]

After the first firing, and assuming that the headspace is sized correctly (.001-.002"), there should be no case stretch. My .284 Shehane cases, also with 35° shoulder, do not stretch. My Warner Tool sizing die sizes the body .0015" and I have it shimmed to push the shoulder .0015-.002 back. My Norma brass is Ø.5525" at the body base and that is a pretty close fit to the chamber. Winchester brass is a little smaller. If the chamber is too small, the "Dreaded Click of Death®" will result unless custom sizing dies are used. [br]
You will see on the SAAMI print that all chamber dimensions are nominal +.002". The nominal body diameter is Ø.5563 at the base, the same as my reamer. It is a minimum chamber. [br]
I run the Shehane at comparable pressures to those of the WSM and get 5-8 loadings before primer pockets are too loose to use. When I buy a new barrel, I determine the largest lot size I will need within the barrel's anticipated life. For the .300 WSM, that would be 400 rounds to shoot the Berger SW Nationals and the National Championship. I acquire and prep the cases, which are enough to burn out the barrel before they are consumed. I expect about 1400-1600 rounds from the barrel using H1000 or IMR 7828 SSC, maybe a little less with H4831 SC. [br]
BTW, here is the link to the .300 WSM. The lower drawing is, of course, the chamber. [br]
http://www.saami.org/PubResources/CC_Drawings/Rifle/300%20Winchester%20Short%20Magnum.pdf

 

[ThunderDownUnder]

Thanks again Steve and you are 100% right! I am looking at the 300WM print as this is the case I want to use not the WSM. I need more sleep, it seems like I missed the point and that is that this thread is about the WSM case. What velocity are you expecting to get with the 300WSM and the 230gr Hybrids? I'm looking at 2800 to 2900fps for the 230 grainers to have a little ballistic advantage over the 7mm projectiles launched at 3000 to 3100fps.

Ian

 

[Steve Blair]

From a 34" barrel, I expect to see ~2950 fps with either H1000 or IMR 7828 SSC, H4831 SC ~2900.