Ultimax 100 “constant recoil” in AR

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Ultimax 100 “constant recoil” in AR

Trinary
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Trinary
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09 Mar 2011, 13:37 #1

My question is basically what it says in the description, is the patented “constant recoil” action of the Ultimax 100 a good idea in an assault rifle?

I was thinking about using the action in order to increase the controllability of a service rifle during auto fire. The main reason behind this idea is this video.

It just seems so controllable for such a light weapon :)

For those of you who don't know how it works it is basically a simple effort to avoid the heavy bolt group slamming against the backstop in receiver. This is done by elongating the stamped-steel receiver (and available bolt travel path) and by carefully calculating the strength of return spring.

I should probably ad that I intend to have the weapon fire from a closed bolt at least on semi, I am toying around with the idea of keeping in open bolt in full auto (the problem with accidental discharges will be handled trough training, part of the reasoning behind this is actually partially to make the soldiers more familiar with open bolt weapons to make them more flexible without the added hazard of accidental discharge)

So is this a good idea?
How do you think it will affect single shot accuracy?

Two more specific points of interest for me:

I also like bullpup weapons for the long barrel combined with compactness (I would rather not have a discussion of pros vs cons of bullpup except if it has to do with the choice of action) but I am concerned about the travel length of the bolt group. Looking at the Ultimax this does not look like a problem as long as the magazine is quite close to the pistol grip (as it is in many bullpup ARs) I am however concerned how well it will fit with the next point.

I would like to have the AR chambered in 6,5 grendel. And I am concerned how well this will work with the design. In regards to controllability and in regards to actual placement of the action in a bullpup rifle. (Will a stronger spring be enough to keep the increased energy in control or will it have to be bigger thereby making a bullpup unsuitable for this weapon?
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Allanea
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Allanea
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09 Mar 2011, 15:48 #2

How is it meaningfully much more controllable than this?
You could have supported Ron Paul. Now you're completely fucked.
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Trinary
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09 Mar 2011, 16:46 #3

Tbh I think it does look more controlable...

And acording to sevral articles on the Defense Review it is claimed the Ultimax offers an 8:1 hit-ratio advantage over the M16 rifle when both are fired offhand on full-auto side by side against multiple targets and that the Ultimax will will outhit the belt-fed FN M249 SAW and MK46 MOD 0/1 at 3-times the range, on full-auto despite being considerably lighter.

*edit* Link to one of the articles
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Trinary
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10 Mar 2011, 15:12 #4

Should I interpret the lack of complaints as a okay sign to start designing a bullpup rifle family (AR, IAR and perhaps a DMR) around the Ultimax action?
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Satirius
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10 Mar 2011, 16:02 #5

The ultimax receiver looks lol long tho
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Falls
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10 Mar 2011, 16:38 #6

Trinary @ Mar 10 2011, 03:12 PM wrote: Should I interpret the lack of complaints as a okay sign to start designing a bullpup rifle family (AR, IAR and perhaps a DMR) around the Ultimax action?
Interpret it as a lack of interest in watching videos and reading the articles linked.

Cite the portions of articles that hold relevance...don't expect people to hunt for it.

Also honestly the Ultimax video you linked...most of it is him shooting at what is effectively a building sized target at very close range and he still has a group that is massive...so it doesnt show anything very impressive.
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Amastol
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10 Mar 2011, 17:02 #7

Constant recoils secret is pretty simple IIRC, prevent at all possible any contact with the rear receiver (there by denying the impact recoil usually cause by such action) by means of a long receiver and bolt travel. this means a decent ROF that's cyclically controllable but it also means a loooong receiver and a relatively large amount of bolt travel. This is fine in a LMG (where the ultimax does just fine from what I've read) but it doesn't make it the most accurate weapon out there.

Remember though that an Assault Rifle is by definition and practice a compromise. It will not be as good as an LMG or GPMG in full auto because its usually shorter and or thinner barrel and usually limited magazine capacity, it is also supposed to be lighter and more mobile than an LMG or other support weapon. Notably its accuracy should be greater than that of an LMG due to its tighter tolerances (since its shouldn't be firing off full auto all the time, for the design difference mentioned) in order to provide better point to point engagement instead of area engagement.

So yes you can make the Ultimax style reciever into a AR, just give it a 30 round mag and a lighter barrel and call it done, but understand that at ~5kg (4.9 empty, even the FAL is only 4.45 kg empty) you are going to have to sacrifice somewhere if for no other reason than soldier comfort. Notably you'll be giving up the equivalent of four magazines worth of 5.56 rounds in weight compared to an M16A4. Im not saying that your weapon will be 5kg, simply that the ultimax's only really heavy part is its barrel, and you will only be able to reduce overall weight by so much.
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no endorse
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Joined: 11 Apr 2007, 01:21

10 Mar 2011, 17:28 #8

So we're clear, a spring does not provide a constant recoil force. "Constant Recoil" just means that the recoil isn't a near-instant impulse.



Also, bullpup does not into really long actions.



Consider this a very strong "no" vote, with a side of "no."



EDIT:
Got a fundamental question for you. The FN-FAL, the M14, the 416, the AKM, and the G3 are all fairly good guns. On the bullpup side, the Steyr AUG and FAMAS are good guns. What does yours provide that equals or exceeds these? (note: "domestically designed" is a valid answer)



You're going about this sort of the wrong way, it's a case of the tail wagging the dog. You don't design something and then come up with its role, you need to define an operational requirement and then design something to meet that requirement. For example (and apologies to others for constantly mentioning this gun):



My gun is the NESR-21. Previously, I operated M14s and AKMs in my armed forces due to a fight over 7.62mm rounds and the usefulness of intermediate rounds. (etc etc etc also I was once a n00b) Therefore, I had ample stockpiles of various 7.62mm tooling and ammunition, and a lot of institutional momentum behind "full diameter bullets" of .30 caliber.

The operational requirement was to replace both guns with a common family of firearms that would be (in descending order of importance)
1. Extremely common (units of the family should be as similar as possible for cost reasons)
2. Simple and easy for a conscript to learn to use. This plays into 1, because similar rifles mean simplification of training down to one platform. This is important, as NE uses dumb conscripts during war.
3. Simple to produce and maintain. Important, as NE issues these to citizens when they turn 18, and dumb conscripts have to maintain these during war. We'll be making a lot, and they'll be heavily abused.
4. Reliable: it can't be something requiring constant skilled maintenance
5. Fire a .30 caliber bullet of some sort
6. Sufficiently accurate that a DMR variant could be produced.



Then someone noticed that 7.62 NATO and 7.62 WARSAW can both be fitted to the same bolt face sort of. (don't try it, you'll blow your head off) So the decision was made to produce a family of rounds with the same base dimensions, for bolt commonality. A variable gas delay allowed action commonality, by reducing the delay a lighter round could be fired, and by increasing the delay a heavier round could be fired.

Thus, the gun fires a family of .30 caliber (7.62mm) bullets from a common action with a variable gas delay. A single gun is produced, which is then matched with different barrel/chamber assemblies (similarly to a shotgun) and apropriate magazines for holding the different rounds.

This meets:
1. can't get more common than 1 gun. To switch between calibers, you swap the barrel/chamber and slap in a new magazine. Boom.
2. it's basically a giant HK P-7. Only weird part is the variable gas delay.
3. See the two above. Nothing too fancy here.
4. Gas delayed blowback is stupidly reliable
5. Check, including a 7.62*55mm round, a 7.62*40mm round, and a hilariously hot loaded 7.62*25mm round that's sort of like a wimpy .30 carbine
6. DMR barrels can be produced easily and effectively.

The common cartridge base also means that any round that fits within the length and width of the action that fits a 7.62NATO bolt face perfectly can have a barrel/chamber assembly made for it. Then you just slap in appropriate magazines.

The downsides are:
-the gun isn't the most accurate: the barrel/action mating point has to be manufactured to a tolerance far beyond what I do.
-It's really heavy. The PDW version (firing 7.62*25mmNE) has an action that weighs as much as it should for a 7.62*55mm round.
-Cheap ammo can lead to fouling in the delay tube, bad.
-.30 cal is not the best caliber.



Well, lo and behold someone figured out that the weight sucked, and that no one really liked the 7.62*25mm PDW variant. So we went and designed a new age M1 carbine that fired the 7.62*25mmNE round that weighs less and, thanks to a gas piston, is slightly less prone to fouling.

IRC wrote:[22:39]Spizania: A chain is a unit of length; it measures 66 feet or 22 yards or 4 rods or 100 links[1] (20.1168m). <<< This is why Britian ruled the world
[22:39]Spizania: we created a system of measurements noone else could understand
[17:57] matinsky theres only one thing that can save saxon england
[17:57] matinsky ...
[17:57] matinsky ...
[17:57] Rosdivan Frogs?
[17:57] matinsky a mark XXXIII bolo
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Amastol
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10 Mar 2011, 18:13 #9

no endorse @ Mar 10 2011, 01:28 PM wrote: Also, bullpup does not into really long actions.
Usually Id agree, the only real caveat would be in a belt fed design ala M60, where you need the standoff anyways.
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Trinary
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10 Mar 2011, 18:16 #10

*Edit* Long post happend while i was typing this I will read thru it. do check my picure of an ultimax and compare the magazine position to a bullpup with the magazine forward (such as the F2000) I think it would fit
Interpret it as a lack of interest in watching videos and reading the articles linked.

Cite the portions of articles that hold relevance...don't expect people to hunt for it.

Also honestly the Ultimax video you linked...most of it is him shooting at what is effectively a building sized target at very close range and he still has a group that is massive...so it doesn't show anything very impressive.
I only put the video in to show were i got the idea from

I did include the important part of the article... That the ultimax is really accurate on full auto.

And i am very much under the impression that he is steering the weapon of free will during the video (I have fired thousands of rounds through both SAWs and ARs and that look like one controllable weapon if you ask me). I am quite sure that that is also the reason that the defence review states that the video seems to be backing up the claims that the Ultimax is really accurate and controllable during auto fire.

Thanks amastol for a good post. I know full well how the action works but you are starting to touch the interesting points.

The lighter weight will of course make it less controllable but read in a magazine (cant remember which sry) that even this version (yes that's an ultimax without stock and with a short barrel) was controllable and useful for CQB. And CQB such as house clearing in where the ARs will mainly use auto fire.


The IAR is another story however and since it features longer heavy barrel and bipod I think it could function like a bullpup Ultimax.

I have also checked some lengths and it should not be a problem to fit the action in a bullpup based on the FN F2000.

I do however have a new concern.
Single shot acuracy... In a regular action most of the felt recoil comes when the bolt assembly slams into the back of the receiver (When the bullet has left the barrel) I will this rifle will be receiving more of its recoil when the round is still in the barrel, the difference should be negligible since the bullet is in the barrel such a short time. One thing that supports this view is that a bolt action rifle is not considered inaccurate just because you star feeling the recoil straight away. But still, It might make a DMR version less accurate...

Does anyone have any comments about single shot accuracy? I can also consider using the IAR for DMR duty's like the L86 LSW since it already has the barrel and the bipod for the job just using it on single action (closed bolt)
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no endorse
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10 Mar 2011, 18:22 #11

Controlability under automatic fire has often been discounted in operational use. But that may depend on how you intend the infantry squad to work.

IRC wrote:[22:39]Spizania: A chain is a unit of length; it measures 66 feet or 22 yards or 4 rods or 100 links[1] (20.1168m). <<< This is why Britian ruled the world
[22:39]Spizania: we created a system of measurements noone else could understand
[17:57] matinsky theres only one thing that can save saxon england
[17:57] matinsky ...
[17:57] matinsky ...
[17:57] Rosdivan Frogs?
[17:57] matinsky a mark XXXIII bolo
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Amastol
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10 Mar 2011, 18:36 #12

I don't think I touched on controlability, Ive always heard its very controlable, I did touch on mobility however; You are still looking @ 4+ kg of 'assualt' weapon even IF you keep the same round (most don't), using a heavier recoiling round (comparatively) is going to suitably increase bolt weight, and receiver length to keep the 'constant recoil' aspect alive at equivalently increased weight.
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Trinary
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10 Mar 2011, 18:37 #13

Good points about designing for a purpose, I am actually doing just that I simply forgot to tell you.

This weapon came partially from an older post about an IAR where i posted
I want a weapon that's in the middle ground between an IAR and a SAW, that is compact enough to be used by mounted troops (helicopter inserted, sometimes via parachute) whose main purpose is to capture installations (so the will be CQB) the troops will then have to defend the installation from counterattack until help arrives so they will also need to be able to "reach out and touch" the enemy. Cost is not much of a issue since its supposed to be used by the glory boys of the Trinary military/"governmental mercenary service"
So the reason for a bullpup with this action is:
Bullpup for short overall length to help CQB while still maintaining the longer barrel for the defencive situation were range is needed

The reason for the action is:
Increased CQB performance due to more controllable auto fire, and common parts and handling with the IAR (that benefits more from the action) thanks Crookfur for pointing me in the Ultimax direction :)

The reason for the 6,5 bullet is:
increased stopping power especially at range but it wont hurt at CQB either (where the increased wall penetration can be put to good effect)

I am making some sacrifices however:
Price will be higher both due to weapon cost and training all the troops to understand the difference between closed and open bolt action (that should be useful for them anyway)
The weapon will also be slightly heavier than the F2000 that it is based on.
Lower magazine capacity due to the 6,5 rounds that will also be slightly counter productive due to increased recoil

PS: Sorry for not posting why I did it in the first place it makes it alot harder to understand.
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Trinary
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10 Mar 2011, 18:50 #14

I don't think I touched on controlability, Ive always heard its very controlable, I did touch on mobility however; You are still looking @ 4+ kg of 'assault' weapon even IF you keep the same round (most don't), using a heavier recoiling round (comparatively) is going to suitably increase bolt weight, and receiver length to keep the 'constant recoil' aspect alive at equivalently increased weight.
This is a question don't take it as something else. Do you really think that the action change would ad that much to the 3.39 kg F2000 tactical, that I am basing the design of even with the grendel round? I know the IAR will be heavier (that a good thing) but this is simply an action change, sure to an action that is probably somewhat heavier but still. The round change could also ad some weight but the 6,8mm AUG only weights 0.1kg more than the 5,56 version and (that number could how ever include rounding so 0,05-0,14kg
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Amastol
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10 Mar 2011, 19:07 #15

The AUG is a pure Gas operated rotating bolt design, which allows for a fairly short operation, and very light weight bolt. This design is a gas unlocked (much like the AUG) but is a rate controlled design that uses a heavier spring and longer receiver length to mitigate recoil impulse and ROF. It may not seem like a major change but since both receiver length and spring will have to be tuned and and in proportion to accommodate the new round (so add the 100 gram increase to that weight as well) recoil force will still play a role, and those dimensions even if all polymer with no metal reinforcement are going to add weight to the design.

Even with rounding yes I still think you'll be looking at a comparatively heavier design.
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