Remington 742, 7400 and 750.
I've been told that the 742 had a design flaw that caused excesive wear to ???? (rails?) I can't remember for sure about what got the excessive wear. So I guess first question is, what was the problem with the 742? Second question. Was this flaw corrected with either the 7400 or the 750? Do you know of any reason not to buy the 7400 or the 750?
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It's really not a flaw, the rails wear and cause failure to feed , Remember these are hunting rifles not meant for repetitive pounding. I've got a 742 that I've had for 20 + years that has accounted for well over 30 deer and a couple of moose and 2 caribou. I've probably put 40 boxes or so thru it maybe more, never once did it fail 0 -
The actual flaw being questioned was that the bolt head in the 740, and 742 was harder than the reciever itself. This in a lot of instances, but not all, caused premature wear of the rails in the reciever that carried the bolt. Of course the, reciever is the indispensible part, that is not replacable, or at least as replacable as the bolt.
Another big thing with these rifles, the 7400, and 750, are the need to KEEP THEM CLEAN. The actual design does not easily allow this. My late father had both a 740, and then a 742, and I do remember having to clean it for him.
As for my choice, if I were in your shoes, I would get either a Browning BAR, or the Winchester SXR. They are basically clones of each other, as they are made by the same company, with different labels on. They are more dependable, and the Winchesters are about the same fare as the Remingtons these days.
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quote:Its sad Remington pushed that design for all those years and then in the end would not take them in for repair.
Yes it is sad. Although in the 70's and early 80's, they would exchange the worn out 740's, for the 742. That was just the barreled reciever too. They used the trigger group from the old 740 being swapped out, and the wood. That is how my late father ended up with the 742, actually. Then he got a model FouR in 1983, which was a real turd, and had gas/cycling problems right from the get go. Thart is also when they started the 7400 series.
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The flaw in the 740/742 is that the "bolt latch" pictured as #11 http://www.gunpartscorp.com/catalog/Products.aspx?catid=4338
has a tendancy to alow the bolt head to want to cam into a breach locked position while the bolt is in full recoil at the rear of the reciever. This makes the thread like locking lugs of the bolt bite hard into the bolt guide rails at the rear of the bolt travel area in the reciever. After a while the rails can become quite chewed up by those locking lugs. I had one such 742 come into the shop that would lock in the open position every other shot due to the bolt twisting into the newly formed chew grooves. Numrich Arms had on ocasion recieved 742's with cracked recievers from the bolt caming in the rear most position. The major difference in design change to the 7400 is they use a square recoil lug on the bolt head instead of the thread like ones. This up grade has a far greater surface area against the rail to absorb the bolt caming should that become prevalent to the weak design of the bolt latch. I have had quite a few 742s in the shop with chewed rails, making the action rough. My fix was to file out the raised chew marks and stretch the bolt latch spring a bit to give the latch a tiny bit more resistance against "bouncing" out of lock out position at full recoil. Also the majority of these hunting guns would get their bores "cleaned" so to speak by the pre season sight in shots. Those dirty barrels, would IMO raise the bolt velocity in its cycleing, increasing the chances of bolt bite. The Remington autos were hotly ported from the git go and would cycle mild loads reliably. This porting gave the gun a high reputation in reliable function in all kinds of conditions and would run even when absolutly filthy with dirt, sticks, pine cones, you name it, I found it in a 742 action and they still ran fine. I shot my first dear with a 06-742. Its sad Remington pushed that design for all those years and then in the end would not take them in for repair. Hope this clears up the 742 mystery out there.0 -
"has a tendancy to alow the bolt head to want to cam into a breach locked position while the bolt is in full recoil at the rear of the reciever."...........xt above, has this correct. additionaly the only way to clean the bolt and bolt latch is to remove the barrel (gummed up bolt latch=chewed up receiver). once the receiver is chewed up the rifle is a one or (at best) two shooter. 0 -
"any other reason not to buy a 7400"
Find a rifle and try to quickly change the magazine after the last shot was fired.
With the bolt open on the last shot....you need to close the bolt on an empty chamber to remove the magazine. The mag has a sliding type lever on the side to close the bolt, but it is hard to accomplish. Then you need to tip the new mag into the well at the correct angle to snap it in.
It's an arse backwards design, you just cannot reload quickly.0 -
Hello, xtriggerman Not new to GB just never replied to any threads but read your analysis on the malfunction in detail on the 742 ...Very well detailed and correct as I've tried everything in getting one of these to function correctly..It is a real balancing act...The bolt latch does under recoil at the end of the bolt travel "drop" to allow the "unwanted" twist in the carrier to set it in a lock up status prematurely before it reaches the barrel extension lugs causing a jam on its way back as its not meant to travel the rail in that orientation...I've had a confusing amount conflicting of symptoms which could lead one to blame the mag or the rails...The rails on mine weren't too bad so stoned them down a hair but to make a long story short every possible aspect of a failure was attempted to be remedied...The latch still however drops occasionally when it shouldn't..I did improve it some by "making another pin out of .087 drill rod .280" long and have a lot more tension along with a new latch and bolt carrier to possibly take up any slack from the rail wear...fuction improved but still not reliable...Also why do you feel the dirty barrels would increase bolt blowback velocity as I would think the orafice would become slightly blocked to allow less gas to the piston?.... Remington from what I read attempted to cure the prob by dropping a #7-1/2 led shot into the recess below the spring to add tension to the latch; the .280" longer plunger should mimic this...Can you explain a possible cause why the latch is dropping as I would think it should want to stay in the up position from the momentum...Have you tried creating a sharper angle on the rearward most tapered end of the "latch" to maybe keep it from rolling under the carrier so easily? Thank you for any response....Mark 0 -
quote:Originally posted by tsr1965
The actual flaw being questioned was that the bolt head in the 740, and 742 was harder than the reciever itself. This in a lot of instances, but not all, caused premature wear of the rails in the reciever that carried the bolt. Of course the, reciever is the indispensible part, that is not replacable, or at least as replacable as the bolt.
Another big thing with these rifles, the 7400, and 750, are the need to KEEP THEM CLEAN. The actual design does not easily allow this. My late father had both a 740, and then a 742, and I do remember having to clean it for him.
As for my choice, if I were in your shoes, I would get either a Browning BAR, or the Winchester SXR. They are basically clones of each other, as they are made by the same company, with different labels on. They are more dependable, and the Winchesters are about the same fare as the Remingtons these days.
Best
EDIT 1
quote:Its sad Remington pushed that design for all those years and then in the end would not take them in for repair.
Yes it is sad. Although in the 70's and early 80's, they would exchange the worn out 740's, for the 742. That was just the barreled reciever too. They used the trigger group from the old 740 being swapped out, and the wood. That is how my late father ended up with the 742, actually. Then he got a model FouR in 1983, which was a real turd, and had gas/cycling problems right from the get go. Thart is also when they started the 7400 series.
Best
I would not touch one with a 10 foot pole (Remington auto rifles)
Tried them before, had enough.0 -
I researched the improvements on the 7400, what seems to be the prob with these upgraded models? The rail issue was addressed and the bolt latch has been eliminated too along with a more coned breech and larger locking lugs to eliminate the peening or atleast spread it out for the most part...Also I can see a hardened insert in the upper inside machined recess..I just purchased a NIB 7400...Customer had a 742 with the usual issues and wanted the 7400...Cut it (the 742) down to 16" did a 5/8-24 thread and nice crown, press fit a machined .825"x 1.250" shoulder for a Liberty suppressor for him to use as the barrel dia. was .660" which wasn't really enough to shoulder the can on and the job turned out excellent...but the Jam issues on the 742 had me skeptical when he wanted me to do this for the 7400 also which I'm starting this week for him...Picked up the NIB not even cycled 7400 yesterday...Really tight so I hope there is no issues with this firearm..This guy will never shoot even 1000 rds. in his life...What were the issues with the improved 7400?...Mark 0 -
I generally have no use for autoloaders that aren't belt fed.
Yep the bolt ate the receiver. Kept cleaned and lubed will help them last, so does not shooting them much.
+1 for the Belgium BAR that I had - cycled flawlessly after I replaced the rotted rubber shock absorbers and old tired recoil springs.0
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