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Foster Manson Reamers

11 May 2019
@ 09:54 am (GMT)

Nathan Foster

Hi all, just a heads up that the Foster Manson Reamers are all set to go.

Full details here (see PDF download):

I am not sure where Clive Judd is at with his stocks. He had a terrible time of it for a while as can happen in business (I really get it). As far as I am aware, Clive has been making and selling stocks but working within a lower capacity (no website) to prevent any backlog of orders. I have no idea when he will be ready for commercial sales and should not really have showcased the stock (added pressure to him) in the reamer video but hell its a good stock. I still want to get more footage of that rifle in the field but am still under a heavy workload at the moment.

Glad to have this off my back, its been a heady time. We are still engaged in other research projects at the moment, unfortunately I cannot really comment on these.


12 May 2019
@ 02:36 am (GMT)

Lane Salvato

Re: Foster Manson Reamers
This is the beginning of a revolution. The 30-06 will now fly like a 6.5 and hit like a freight train. no more back shelf for dad's '06. It's now the cartridge to have.
12 May 2019
@ 03:18 am (GMT)

Joshua Mayfield

Re: Foster Manson Reamers
Congratulations, Nathan. I hope these reamers catch on and accomplish some positive things for hunters and for the Foster family business, in particular. I share Lane’s excitement for the .30-06 and am eager to see what a 300 WM FMR can do. I look forward to reading, as users multiply, how the revised Winmag compares and contrasts to the 300 PRC which has every appearance of becoming a commercial success.

Thanks for your dedication, Fosters.
12 May 2019
@ 07:51 am (GMT)

Nathan Foster

Re: Foster Manson Reamers
Hi Joshua, thanks for your kind words.

Just to be clear, there was nothing in this for us. I started this whole deal because I felt (following previous experiments) that it had to be done. I don't know why I felt it was important to help folk, I just knew that there were problems that could be fixed (the photo of the .30-06 problem rifle groups was an A-typical example). We get zero return on any of this work over the past year or so. I guess by the same token you could take that as meaning that because we have nothing to sell or gain from this, it might give some assurance that this is not just some new marketing BS.

That aside, it may bolster my own portfolio of achievements leading to more book sales which may help to cover some of the time and expense of this. I don't want anything from Dave Manson. He is my friend, not a money tree.

The last .300 had its sweet spot at 2960fps with a 208gr. The Test OAL was a shade shorter than as listed on the pdf. As a contrast to this, the PRC loaded to 3.7 is still well off the lands and needs a Wyatt box to either get close or chase the lands. So while the PRC has great merit and geometry, there are some idiosyncrasies to it.
15 May 2019
@ 07:00 am (GMT)

John D. Hays

Re: Foster Manson Reamers

Nathan Question:

Here in the States there is a plethora of .older 30-06 rifles, very many of which are military bolt-action conversions, and new .30-06 still sell.

Is it possible to take a rifle with standard .30-06 chambering and simply have it rechambered with the .30-06 AI FMR,or would it require a barrel setback before reaming?
15 May 2019
@ 07:33 am (GMT)

Fernando Cundin

Re: Foster Manson Reamers
To Nathan,

I also have the same interest and question as John Hays.

Also, would current new production 30-06 rifles benefit from the standard 30-06 FMR reamers?

15 May 2019
@ 09:34 am (GMT)

Nathan Foster

Re: Foster Manson Reamers
This question has been coming up in my inbox for the last 48 hours or so. Glad you asked here on the forums.

Due to the neck and throat tolerances, the barrels need to be set back by a half inch (for all FMR reamers) if rechambering over an existing chamber.

Further to this, the .30-06 loaded with heavy bullets at high velocities produces pronounced harmonic effects. In a lighter (sporter) barrel gun, you can see the POI shift with incremental charges. Therefore, the knox section of the barrel (start of the barrel) really needs to be parallel for some distance. For a dedicated LR rig, I would suggest 2" minimum. Taper as you see fit thereafter.

If you do not have much of a knox form, then the barrel will need to be shorter (if the contour is thin). As an example, a 1" to 1.5" knox could be finished in the same manner as a Vanguard 24" barrel. Alternatively, it could be finished at 26" with a heavier barrel but I still suggest that the weight be centered via a longer knox / parallel. I am sorry guys, some of this is hard to explain. Those who trust me will trust me, those who don't won't.

Many rifle barrels have an immediate taper. These are a no-go.

Note also that the premise for the .30-06 becomes moot as we go shorter than 24". The Superformance burn rate is the same as H1000 (but with a higher bulk density) so it really needs to be up at 24" or longer for best results if chasing high velocities. Of course, you do not have to use the reamer / rifles in this manner.

(Completely off topic - the word knox form comes from an English term used to describe the flat milled section on a Lee Enfield barrel, utilized for alignment of the sights during fitting. The term is now used here and there throughout the industry to describe this general area of the barrel. There are a lot of words used in this industry that do not match the actual physical properties of an item).
15 May 2019
@ 01:16 pm (GMT)

Jonathan Kitterman

Re: Foster Manson Reamers
Is it just the .30-06 or do other combinations need the knox?
15 May 2019
@ 01:47 pm (GMT)

John D. Hays

Re: Foster Manson Reamers

Is it because of these harmonics that you typically bed the Knox?
15 May 2019
@ 08:53 pm (GMT)

Thomas Kitchen

Re: Foster Manson Reamers
just to clarify
can you confirm that you can turn a 7mm rem mag into a 7mm practical without setting back barrel please Nathan.
also thank you for note on the origin of the word knox.

John bedding the knox can help relieve stress on an action if your hanging a heavy profile barrel off it.
16 May 2019
@ 08:14 am (GMT)

Nathan Foster

Re: Foster Manson Reamers
Hi Jonathan, as Thomas said, it helps alleviate strain on the action (when bedded) and makes a meaningful difference to harmonics. Its becoming a forgotten factor as the barrels get heavier but the cartridges get weaker. It helps to have a good knox section on any rifle producing high power. A tall tree needs strong roots to stand up to the wind.

Hi Thomas, this is a good question that has been asked by several U.S smiths. Its a good idea to table this here. the 7mm Practical can be used without setting the barrel back. But just to be absolutely clear, the neck area of the 7mm Mag is not completely washed away (much like a Redding neck bushing die does not completely size the entire neck. Therefore, if the neck of a 7mm Rem Mag was say .320" and you ream with the Practical at .316 (or most recent version at .317) there will be a slight step at the beginning of the neck.

In practice this step cannot be seen. We have studied this carefully (also visually using macro photos of brass). The step is indiscernible and should be regarded more as a taper. Accuracy appears to be the same as always - excellent. The 1:925 Sendero and LR Hunter rifles appear to go extremely well. The benefits certainly outweigh any theoretical negatives.

The 7mm Practical, 7mm Rem Mag FMR and .300 Win Mag FMR should all be head spaced as per the gunsmith notes on the 7mm Practical page of this website.
17 May 2019
@ 10:43 am (GMT)

Nathan Foster

Re: Foster Manson Reamers
Another question:

My friends are not understanding the re-design thinking of it like an AI design whereby the shoulders taper differently and cases need to be fire-formed. I don't understand the interior dimensional changes enough to be able to help them.


1. The body dimensions are generous so that you can hand load to high velocity or use +P type factory ammo.

2. The neck dimensions are tight for accuracy, but not so tight that you are forced to neck turn.

3. The throat dimensions are tight but with gentle angles to guide the bullets into the lands. This geometry (length and angle) distance the OAL's was selected for best power, accuracy and long term wear (most folk neglect this last aspect - chasing the lands).

4. The 7mm's use some of the geometry from my 7mm Practical to enhance performance. But in the .30 cals, the throats are entirely unique, there are no other .30 cals like this. The goal here was to get max speed with minimal pressure but also with a short OAL in the .300 Win Mag so that it could for example still fit an M70 action.

5. The shoulders are unchanged on all FMR cartridges. These are not wildcats. They are designed to shoot factory ammo well.


We are a small, family run business, based out of Taranaki, New Zealand, who specialize in cartridge research and testing, and rifle accurizing.