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> 7mm Practical
7mm Practical
@ 07:15 am (GMT) |
louis georgesI am having a 7mm practical built. The reamer is a David Kiff reamer the only difference is my reamer has .172 free bore. The Dave Manson reamer is .168 free bore. I want to shoot 168 VLD Bergers because I have a lot of them. H1000 powder will be used. Looking for a starting powder charge. also what I can expect for max velocity from a 26" barrel? As always Thanks for your help. |
Replies
@ 11:31 am (GMT) |
Nathan FosterRe: 7mm PracticalHi Louis, if your smith has the confidence to do so, you might want to ask him if he could grind the throat right off this, then use a throat reamer to cut the chamber to suit.If possible, you want the 180gr ELD-M to have a COAL of 3.622 or 92mm. Acceptable error is 10 thou or .2mm forwards. Unfortunately, the stated lead of .172 is not sufficient information on its own as the angle has an exponential effect on the final OAL. So in this instance, it would be best to start with no throat and have this cut afterwards. Very hard for me to explain otherwise sorry. |
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@ 12:42 pm (GMT) |
louis georgesRe: 7mm PracticalIt is a reamer that you and my friend have designed, same as the Manson reamer but with longer free bore by .004 it is 1deg-30. And once again thanks. |
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@ 12:53 pm (GMT) |
louis georgesRe: 7mm PracticalSorry Nathan, Should have checked in your book Long Range Hunting Cartridges first before sending off an email. I new I had seen the info I was looking for. Found It in your book. But your new Practical "2017" does not have the 168 gr berger. Once again sorry to bother. |
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@ 08:09 am (GMT) |
Nathan FosterRe: 7mm PracticalNo worries Louis.It is time and experience that has lead me to the above suggestion. Even when the angle is listed, it may not have a bearing on the actual angle as cut. This occurs when reamers are made individually. It can be very hard for the reamer maker to get this exactly right and to predict a COAL on made to order reamers no matter who makes the reamer. So again, best to grind off and start fresh or send the tool to PTG and have them grind it for a very small fee. This has been an ongoing learning experience for me. In the past, I felt that having a fixed lead built into the Practical (as PTG were doing when asked by customers) was OK for those who insisted on it. But the drawing had no actual bearing on outcomes and this is something that you cannot blame them for. And again, it is hard for me to go into further detail. All I will say is that the fixed leade one-off PTG Practical reamers are generally best ground back. The throat can then be cut to exact specs. I suggest using my above OAL specs for the sake of throat wear and other factors. Hence why I wanted to see the design ratified as there are many variables that shooters often fail to take into account. |
@ 07:14 pm (GMT) |
Thomas KitchenRe: 7mm Practicali thought i would just talk about my learning curve with this reamer design stuff.so as some people know i shoot a 308 norma mag when i was planning this build i had to buy a reamer. Dave manson, Nathan and i tried to design a throat to suit the 208gr amax's we done pretty well but it did end up a little longer then we expected. the bright side i snuck a little extra velocity out of it, the down side is i had the magazine extended to what i thought was the length but its to short now. ill get magazine lengthened to the 225gr eld-m load im shooting anyway so its all works out in the end. the latest project is a 6.5 rem mag, once again i needed a reamer. i looked at a few options like copying the throat of the creedmoor but in the end got the throat ground off it. i supplied a dummy round to my gunsmith and he used a uni throater to match that. it makes life a lot easier. it should be here tomorrow so im getting excited. if its your friends reamer you should be able to get him to give you a coal of his chamber with your chosen projectile. |
@ 06:22 am (GMT) |
Greg QuickRe: 7mm PracticalHaving many woes with my David kiff fixed lead reamer on my practical. Throat was cut so long that my oal is about 3.733. From the get go it was hell trying to fit a Wyatt magazine box in the existing stock that was milled for a seekins bottom metal because the cartridges were far too long to feed in a standard magazine. Even with a Wyatt mag box the cartridges are still too long using the eld-ms. I am forced to use either eldx's or lighter loads. I've had to resort to buying a new barrel(on its way as we speak) and have it rebarreled using Dave Manson's reamer. Just giving you my own experience with the Kiff reamer you're planning to use. I don't have the experience to tell you one thing or the other, that's Nathan's job. I'm just telling you my story. I've been putting Nathan through hell trying to figure my practical out with My practical and the fixed reqmer from ptg and it's just come down to rebarreling for me. Not entirely blaming the reamer as Nathan has suggested it could be the high finish of my barrel. The biggest problem is how long my rounds ended up being and is pretty much a single shot rifle as it sits. |
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@ 11:05 am (GMT) |
Nathan FosterRe: 7mm PracticalJust some further notes on this.1. The correct specs for the Manson reamer are as follows: The name of the reamer is Revision C (B was PTG). The reamer should have .130 freebore. The first few Manson Reamers had .168 freebore but this was incorrect as it was based on inconsistencies within the former design, attempting to take measurements from a fixed throat unit. Anybody who owns one of the very first Manson reamers (there should only be a few) can have these remade to the correct specs at no cost other than shipping charges. The current Revison C is batch produced and as loaded into the CNC program, should have no issues from batch to batch. The OAL is desirable for all bullet weights and types when housed in the M700 and clones, offering full velocity while leaving just enough room for throat wear / good barrel life. 2. Keep your builds simple and avoid extremes. If you go too light or use an action with an insufficient mag length, the rifle will be an annoyance and the barrel will overheat (including wrapped barrels which cook on the inside). Along with this, you may end up wanting to apply add ons to tame its recoil. If you go too heavy, the rifle may lose its simple appeal and again, OAL can be an issue in tactical builds with detachable mags. Ergonomics can be a problem with free standing grips in the magnums. They look the part, but once you carry them a ways and have shot them for a while, they can lose their appeal. A lot of this pain can be avoided. There are Hollywood guns and then there are guns that get the job done. The more we stray from the middle ground, the more the 7mm Practical concept steers away from its original premise and the more problems we may encounter. Keep the build simple and learn how to hold it and shoot it properly. That is all that it takes to get optimum results. When David Manson shot his pig in the head at 670 yards with the 7mmP, he turned and said to me, "man this rifle is easy to shoot". Thats how this is supposed to be, how I would like to see your builds turn out. |
@ 01:29 pm (GMT) |
JOHN HAYSRe: 7mm PracticalI’m sure I am late to the game, but if I were to build a 7mm Practical rifle from a Remington 700 Sendero or such, what caliber would be best as a base rifle? I would like to avoid as much magazine modification as possible, etc. I would be having a new barrel, but wish to keep the same stock and not have to modify the action. |
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@ 01:29 pm (GMT) |
JOHN HAYSRe: 7mm PracticalI’m sure I am late to the game, but if I were to build a 7mm Practical rifle from a Remington 700 Sendero or such, what caliber would be best as a base rifle? I would like to avoid as much magazine modification as possible, etc. I would be having a new barrel, but wish to keep the same stock and not have to modify the action. |
@ 02:36 pm (GMT) |
Jonathan KittermanRe: 7mm PracticalIf you get a new Sendero in 7mm Remington Magnum, you can either shoot it until it needs a new barrel or have a gunsmith change it over to the Practical.I am not sure what model of HS Precision stock is coming with the current Senderos. Some prefer an earlier model with a smaller palm swell, if I remember correctly. Rifles based on the .30-06 cartridges would need a bit of modifications during a re barreling to the practical. Opening the bolt face, installing after market extractor and maybe opening the feed rails. I didn't look at the books but I think a lot of the information is in there between the Cartridges and the Rifle book. |
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@ 06:30 pm (GMT) |
JOHN HAYSRe: 7mm PracticalYes, I was thinking to get a Sendero 7mm Magnum and shooting the barrel out before trying the Practical. Or just immediately replace the barrel and sell the unused original.Thanks for the advice. It reminds me of when we used to do SCCA racing. We would bust ourselves to buy a brand new car, then strip it and sell all the parts we didn’t need. In that way we didn’t have to fight used or worn components. We lost money in the short run but made up for it in length of car life. |
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@ 06:59 am (GMT) |
Nathan FosterRe: 7mm PracticalHi John, any of the magnum Sendero's will be fine including the RUM's. All have the same magazine length and all feed fine.Yes, you can shoot the barrel out or ream the existing barrel of a 7mm Rem Mag immediately. Apart from that, Jonathan was correct regarding minor changes to the long action in standard calibers and also his comments regarding the stock design. |
@ 11:03 am (GMT) |
Brent WatkinsRe: 7mm PracticalHow do you know what reamer design you have? I got my reamer from Dave earlier this summer. The rifle is already built and in final stages of load development. |
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@ 09:03 am (GMT) |
Nathan FosterRe: 7mm PracticalHi Brent, the finalized max COAL with the 162gr M should be around 91mm (3.582) and with the 180gr M around 92mm (3.622). But the key factor is mag space. If the ammo feeds smooth through your mag and you have room to spare, then all is well and good.I'll say this again. lately I have been seeing more and more "tactical" 7mm Practical type builds. The two factors to be weary of regardless of the reamer used are 1. mag space and 2. False ergonomic advantages. I see owners drop big money on tactical stocks which look the part but fit poorly. They will then lie to themselves to justify the purchase (we are only human), even when the stock does not feel right. This is a slippery slope because once you start bullshitting yourself, it begins to color other variables and plays hell with problem solving. |
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