Lawton M7500 BR receiver, Manner stock and Rock barrel tests started.

Fiftydriver · #8 10-20-2006, 09:05 AM

Oldfamily,

I guess as far as ultimate structural failing limits, the dual port receiver is weaker then the single port. In all honesty, the next one I order for one of my personal hunting rifles (there will most certainly be more!!!), will be a right port only receiver. I just wanted to try out the true BR design and see what I thought. I like it but for a big game rifle there really is no need.

Strength wise, there is so much steel under the ports and a very substantial top strap as well that I suspect you would never be able to tell any difference in strength between the two designs.

Also, if you look at that rail base its solid steel when you order them. Mine has been milled out in non critical areas on the underside to reduce weight which is a good thing as it would not have made weight otherwise.

But as they come from Lawton, those rail bases have alot of steel in them and only add to the rigidity of the system.

Them combine all that with the longer threaded section and the full length bedding of the receiver and this system is as stable and solid as any other receiver out there of the same diameter.

On the stock, I am not sure if the stock could be ordered with a wider forend or not. I know Tom is working on some new stock designs but I am not sure if that is one in the works. He would be the man to talk to. Go to www.mannersstocks.com and you can e-mail him and see what he has to offer in a wider forend. I would like a slightly wider forend but so far have not found any fault with this one.

Basically this will be a torture test to see if I can make this barrel tear apart the 200 gr ULD RBBTs. I suspect I will not be able to do this even at very top end safe pressures in this rifle. For the time being I think Rock really hit this one on the head!!

Kirby Allen(50)

Fiftydriver · #9 10-20-2006, 09:06 AM

Eaglet,

Whenever your ready my friend!!! [img]/ubbthreads/images/graemlins/grin.gif[/img]

Kirby Allen(50)

Fiftydriver · #10 10-20-2006, 09:07 AM

Wildcat,

You will be very happy with your rifle I assure you!!

Kirby Allen(50)

Fiftydriver · #11 10-20-2006, 09:13 AM

Reed,

I will admit that I have not used alot of cut rifles barrels on my personal rifles. I have used alot of them for customer rifles and those from Rock and Krieger have shot very well, on par with all the other top end barrels out there so I am very happy so far with this barrel.

It did take a bit longer to break in then the Lilja barrels I am used to but once it turned the corner is was very similiar, fouling just seemed to stop pretty much. Well, as much as it will when shooting 200 gr 7mm bullets at just shy of 3300 fps!!

The Lawton M7500 has alot of great features and I am working on Barney to offer me one more feature but I do not want to talk about that until I get a solid decision from him either way. If he will do what I want I think his receivers will offer everything the Nesika Baw M receiver will and at 1/2 the price!! I just have to find time to call and talk it over with him and see what he says.

If he agrees to it I will be using his M7500 exclusively on my custom rifles unless a customer wants something different.

So far the rifle is performing very well, time will tell but I suspect it will continue to shoot very well. Generally if there is a problem you start seeing things right away at least if its with the land widths or over spinning.

I think every round I have designed has been exactly what you describe about being on the edge so I guess we think alot alike!!! [img]/ubbthreads/images/graemlins/grin.gif[/img]

Kirby Allen(50)

TMR · #12 10-20-2006, 08:00 PM

I did some initial velocity testing at the shop and found that the new Rock barrel design needed significantly more powder to match that of the Lilja barrel but also allowed more top end velocity potential. At 105.0 gr US869 I was averaging 3265 fps with really no pressure signs at all. In my Lilja barrels I was stopping at 102.0 gr with 3175 fps and similiar pressure sign on the case head reading the extractor marks which are extremely faint but just visable.

Kirby,
Is this comparing to the 1-8 3 groove Lilja or the 1-9 6 groove barrels ? I was hoping to be able to reach 3250 or so with the rifle you are building for me.

wildcat · #13 10-21-2006, 01:11 AM

Kirby, I can't wait to get her, and I am glad to hear the Lawton actions are working well.

Jake

Fiftydriver · #14 10-21-2006, 09:16 AM

TMR,

Your barrel is a 1-9 6 groove so you will have no problem getting the level of velocity you want easily. My reference was comparing the Rock to a Lilja 1-7 3 groove.

The slower twist will get you exactly what you want, no worries. I am just as happy with the Lilja 1-9 4 and 6 grooves as I am the newly designed Rock 5R barrels so just adds another top end viable option!!

No worries, your set.

Kirby Allen(50)