A "Real" Mosin Reamer

[Grindl]

Good news folks . We may have a real workable M-N reamer available very soon . I've been working with David Fair of Coyote Creek Armory , and Dave Manson , of Manson Precision Reamers to develop a reamer for my "F"gun project . Hopefully ; the first one should be ready and on the way to CCA early next week .

If this works out ; we in the Mosin community will have a source for tight reamers that have the correct amount of "Free-bore", so you won't have to watch your bullet fall out of the case , as you try to get a OAL or Case to Ogive measurement .

The problem for us M-N people is the reamer manufacturers all base their M-N reamers off of CIP standards . Nothing wrong with that ; except somewhere along the way , CIP adopted the blueprint from the UK-59 machine gun barrel , rather than using the print from the M-N . So the majority of reamers made for Mosin's had a ridiculous amount of "Free-bore" made into the reamer . Translation ? The distance from the case mouth to the throat was about two and one half times longer than it should have been , or needed to be . Machine guns need that long spacing to help reduce barrel temps , friction and throat erosion . Rifles don't .

My part in this whole deal was to spend a lot of time with a Hornady OAL gauge , and a stupid amount of different Target bullets , compiling pages of data to send to Mr. Manson , along with additional information gleaned from half a dozen knowledgeable and expert sources , regarding ballistics and L/R shooting .

For those who are not aware of Manson Precision Reamers ; They supply many of the top competition shooters in the country with custom reamers for their rifles , for both F-FTR-F Open , Palma and the PRS shooters as well .

So as soon as I get my "revised" action back from David , at CCA I will post the results for all to see . And knowing what I've learned about Mr. Manson's products from a large group of his customers I think we will have a excellent reamer source .

[Grimstod]

This has already been done. Give Joe at Anacortes Prototypes a call. He designed a remed for 308x54r. Has the shorter freebore for 168gr bullets. Neck is best of unturned brass and 308 bullets. If you shoot 311 out of it then you would need to neck turn. Its a pretty tight reamer. My forster dies are a good match for it.

[Grindl]

The purpose for doing all the research for this reamer was/is to have a reamer available with the correct "free-bore" to accommodate the newer generation 175-185-195-200-210 & 200.20X target bullets in .308 caliber . Dummy rounds ; with both Sierra 185/TMK and Berger 185gr Juggernaut were sent to Manson Precision , along with data from Brian Litz regarding the recommended free-bore length for 200.20X Match bullets .

A correct free-bore length for a 168gr bullet will not accommodate the longer 185gr VLD , TMK , 200.20X or heavier bullets without stuffing it deeply into the case to achieve current users Base to Ogive Length . A corrected free-bore for the heavier , longer VLD's & TMK's allows the round to be loaded to a "corrected" longer OAL that will allow for increased powder loading , while maintaining a safe chamber pressure , without sacrificing velocity . And allow for adjusting the CTOL off of the throat .

It has been pretty solidly proven ; that 168gr bullets are excellent for 300 or 600 yard competition but they are deficient when attempting to shoot them at 1,000 yards . The biggest factor is cross-winds / wind drift , and the 185's and heavier counter that better . We need to have a rifle chamber that can shoot and adjust the rounds....

Developing this reamer was just another step in advancing the Long Range accuracy potential of a M-N action rifle .

[Grimstod]

Getting into gunsmithing so I am going to be getting a fe reamers. Probably a 311 with shorter throughout for 174 Sierras. Another 30x54r for long 200gr bullets. And of course my wildcat the 6.5 Lapua. Maybe a few of Adam L Bonds Improved reamers too.

[Grindl]

Good to hear , Grim . Like to hear your thoughts on a near normal length "Improved" 54r case for .308 changing the shoulder to 40 degrees . Got my action back from CCA after the reamer changes , and the chamber numbers look very promising . If I've done my calculations correctly on the Base to Ogive / OAL , Mr. Manson has the reamer , "Good to Go" , for the heavier .308 bullets . I should have some targets in the next few weeks that will tell me if I did it right .