Excess headspace Remington 788

[kamikaze1a]

I acquired a Remington 788 in 243 some time back and it sure grouped better than my other more costly and better looking rifles. Problem was it ate brass. Initially I got case head separations after a couple of firings out of a case. Neck sizing gave me more firings out of the cases and wondering how I can fix the excess headspace? In this case, I am pretty sure it is due to the rear lock lugs of the 788. If I get the headspace fixed the usual way, couldn't the bolt get compressed further?

 

[Jim Watson]

There is a debunking site that says the 788 in the .473 head diameter calibers is subject to case stretching. Do you know your headspace is excessive or is it just that heavy loads are compressing the bolt against the rear lugs?

 

[rcmodel]

Full length sizing will create excess headspace if the die is screwed down too far and pushing the shoulder back.
Maybe that's your problem.

Adjust the FL sizing die down only enough that a sized case will go back in the gun with slight bolt close resistence.

rc

 

[kamikaze1a]

I must admit that I do not know for a fact that I have an excess headspace situation but the results that I am seeing seem to indicate so. I do not have a chamber or case gage for 243. As for die adjustment, I am setting with normal adjustment which is just past cam over but don't have a case gage to check if that is giving me a setback shoulder situation...

Question though, with a rear locking lug bolt, is the bolt compression permanent or only occurs while firing hot loads? And if so, the bolt compresses at firing and springs back after the shot?

 

[Jim K]

A rear locked bolt has a greater tendency to headspace problems due to both bolt compression and receiver stretching. That being said, the 788 is a pretty solid rifle and IMHO it would take a lot of shooting (much more than the average sporting rifle ever gets) to cause either. However, it sounds like the rifle was bought used and a previous owner may have loaded extra hot, which can certainly hasten headspace problems.

But I would not depend on cases; I suggest having a gunsmith check the rifle out. FYI, there actually are no .243 headspace gauges; the .243 and .308 Winchester use the same guages.

Jim

 

[W.E.G.]

If you haven't checked the chamber with a GAGE, you are only guessing.

If I had to GUESS, I would guess your RELOADS are out of spec.

Are you even using a gage to check your reloads?

 

[ranger335v]

"I got case head separations after a couple of firings out of a case. Neck sizing gave me more firings out of the cases and wondering how I can fix the excess headspace?"

First, bolt "compression" or action stretching of the 788 action is very little more than with some front lugged bolts and actions.

Second, RC is correct, it's a resizing problem.

Setting a sizer as you describe often produces too much shoulder setback which produces the effect of excess headspace but even real headspace 'problems' mean nothing to a handloader who resizes his cases correctly. As WEG suggests, using a case gage such as the Hornady tool with a dial or digital caliper to measure the shoulder setback on fired cases and restoring that - and no more - on FL sized cases is easiest. If you don't have such a gage and caliper you can still adjust the die the old way by how the cases feel when chambered.

Back your sizer out a third of a turn or so (about 20-25 thou) from where you normally put it and size a case. Chamber the case to see if you can easily close the bolt on it...probably can't and shouldn't. Turn the die down 1/8th turn, that's about 9 thou which is MORE than the full SAAMI range of headspace from minimum to maximum so don't change it any more per step. Size the case again and try again. Keep it up until you can close the bolt with just a hint of resistance, and back it out a tad if you go too far. When you can chamber your sized cases but feel just a little resistance doing so they are not jammed into the chamber but are snugly fitted so they can't stretch much when fired. Secure the die lock ring at that point and you will be good to go.

Size cases this way your rifle's actual headspace won't matter a bit.

 

[Jim K]

More playing with the loading dies and guesswork. Why not simply have the headspace checked?

Please note that in extreme headspace conditions, those reloading tricks will only increase the danger of an unsupported case letting go and doing serious damaqe.* That doesn't happen often but it is why I don't like the idea of pretending that case sizing will solve all headspace problems.

*True, the 788 is less subject to that problem than some other rifles, but why tempt fate?

Jim

 

[kamikaze1a]

10-4! Cases fireformed to my chamber and sized to match... Maybe should invest in a chamber gage. Thanks!

 

[fguffey]

http://www.charm.net/~kmarsh/788.html

F. Guffey

"Full length sizing will create excess headspace if the die is screwed down too far and pushing the shoulder back.


Maybe that's your problem"



If the die is screwed down to the shell holder (far enough) it is called full length sizing, that is sizing a case that is the same as an over the counter, new, store bought, commercial size ammo, I only have one version of full length sizing, after that I allow the very versatile full length sizer die produce custom sized cases that fit the chamber with the aid of the companion tool to the press, the feeler gage.

But, I start by sizing cases to the chamber as in form first, then fire, others fire first then try to determine what happen.

The 243 is a 308 is a 30/06, or the 243 is a 308 that can be formed from a 7mm57, 8mm57 or the 7.7, no matter what case I look for a case that is too long from the head of the case to the shoulder, by forming the case and moving the shoulder back head space can be determined without firring, knowing when to stop moving the shoulder back is the key, and knowing the case being formed is not going to be fired but used as a transfer and or for those that can measure the length of a case from the head of the case to it's shoulder in thousands ( or measure the length of the case for the effect it has on head space).

There is full length sizing, then there are all the other options, for most it is full length sizing or neck sizing, I have as many as 10 options between full length sizing and neck sizing, with the versatile full length sizer die.

 

[kamikaze1a]

That was a great article. I think my 788 is a great shooter, though pretty beat-up from years of use in the bush. I don't worry about adding another ding since it's showing it's age but sure don't want to give up on her yet. She still shoots straight and hold groups well...just requires new brass more often. I will definitely try changing my sizing adjustment and hope for the best. Thanks!

 

[JohnMcD348]

I love my 788. It is/was my Father in Laws rifle that he bought new back in the late 60, early 70's. .308 with a Meade 4x scope. I took it to the range after it having not been fired in over 20 years so I could site it in and after 8 shots, the next target I shot placed 3 rounds in a group covered by a dime. The shots were made at 100yd, off hand, with the leather sling. I doubt I can repeat that shot but I became an instant fan and haven't looked at another rifle for hunting since. Here's the 4" target.

 

[Sunray]

"...Why not simply have the headspace checked?..." Exactly. Costs little and takes very little time. Mucking about with the sizing doesn't fix bad headspace either.

 

[Jim Watson]

So what do you do if the headspace doesn't gauge to spec?
This was a cheap rifle when new and even though they have a cult following now, one beat up from years in the bush isn't going to be real valuable. Headspace correction by setting the barrel back is not cheap.

The Guffey System of matching brass to barrel will get you by. Unless it has the Keenan Flaw and soon blows you to Perdition.

I don't know The Answer.

 

[Bluehawk]

This was a cheap rifle when new and even though they have a cult following now, one beat up from years in the bush isn't going to be real valuable. Headspace correction by setting the barrel back is not cheap.

I wouldn't say cheap...inexpensive...yes! If it needs rebarrelling or setting back it's worth every penny! I have one in 6mm Rem...would not part with it for any reason!!!!!!
Remington shot themselves in the foot by bringing this rifle to market.

 

[kamikaze1a]

After reading some of the posts and leads and if I understand the major flaw of the 788, rebarreling or correcting excess headspace might not resolve the problem? Might the problem be the rear locking bolt and bolt compression? I guess confirming that an excessive headspace situ was not present would be a good first step but if bolt compression was the problem, the headspace could check out ok?

Would a set of go/no go gages give me a good idea on the headspace?

 

[NCsmitty]

the headspace could check out ok?

Yes it could, but you seem to be consumed with the idea of bolt compression, and that it may be causing your possible headspace issue.
I doubt it, not if you are shooting sane loads that do not stress the action. If you are running maximum loads, then you reap what you sow.

If you listen to what others have mentioned and back off your FL die so that you're not knocking the shoulder back, the brass will form to your chamber, and you'll minimize further stretching of the brass. This will work even if you have some extra headspace.
You need to strip the bolt of the ejector to get an honest feel of the headspace gauges, but you should have it checked by someone, whether you are capable of doing it, I have no idea.




NCsmitty

 

[Jim K]

The "flaw" of the 788, its rear locking is, I suspect, not a real problem unless the rifle has been subjected to far more use than the average sporting rifle ever gets. It would probably take around 4000-5000 rounds of standard loads to create a headspace problem and the barrel will go before that happens. Now if an owner loaded "hot", it would be a different story, but I am talking standard factory loads or equivalent.

Jim

 

[fatelk]

It's not a 788 in .243 with a painted black stock and shorter than usual barrel is it? I was familiar with one like that years ago. Occasionally the brass would come out in two pieces.

 

[kamikaze1a]

It's a standard rifle barrel'd 243. For some reason, even with "starting loads" the primers appeared to be flattened by a hot load and have to back off a bit. As I mentioned, if I partial sized or adjusted the sizer to only size the neck, it seemed to give me better brass life. I ordered a case gage and will drop a fired shell into the gage and hope I don't turn out to be extremely long.

I guess I am back to my original query, is bolt compression a momentary compression or a permanent shortening of the bolt? Does it compress and stay compressed or only compress' during firing?

Thanks!

 

[Vmcnew]

Bolt compression is both a temporary and a permanent thing. With a standard load (not a hot load that so many folks on this forum seem to like) one that does not exceed 50000 cup there should be no bolt compression of the temporary variety. If your loads are producing pressure in excess of the design specs of the action then a degree of temporary compression will occur with each firing. Over time (how long depends on how much you're exceeding specs) the repeated compressions could cause slight permanent bolt compression. It is more likely however that the repeated compressions will alter the shape of the locking lugs. In either event the rifle action has been altered, and the solution is to bring the barrel into proper orientation with the new shape of the action. This could be done by removing the barrel, and machining a couple of thousands off the barrel shoulder, and then adding one thread to the shank, and then reinstalling and rechambering the barrel, it may also be necessary to remove a couple thousands from the chamber end of the shank. Because the rifle sights need to be on top, you will have to work in full thread increments, and that may produce more movement than you need. Long story short the only time you will see temporary bolt compression is when you exceed maximum safe working pressure. If your load is in spec, then the problem is not temporary, it is caused by compression or damage that has occurred in the past and can be corrected.

I would not suggest just putting a bandaid on the problem by sizing the brass to fit the chamber. You need to find out what is going on with this rifle, and once you have found out decide then what course of action to take. If the rifle does have a mild headspace problem, sizing to fit your chamber and loading normal loads may be a solution. Step one is to check, or have checked the head space. If that gives you a normal reading then something else is wrong.
Have you used this load before? What do factory rounds look like fired in the gun? Mic a case that you have loaded, and compare that to a factory load, fire both and then mic them again. Do they match before you fire them, how about afterwards. If they don't match before hand but do afterwords then the problem is most likely headspace. If your fired case is longer than the fired factory case afterwords, then the problem is in your load, It is either out of spec pressure wise, or your brass may have exceeded it's useful life.
Your primer issue could indicate a pressure problem, or a head space problem. When you fire a round the firing pin strikes the primer driving the case all the way forward in the chamber and eventually detonating it, the brass expands and grips the chamber wall. As pressure builds the primer is forced out of the pocket slightly until it contacts the bolt face, as the cartridge reaches full pressure the case head stretches back slightly until it to contacts the bolt face flattening the primer and forcing it back into it's pocket. If you have excessive space here then it could show in the primer being flattened even at lower than normal pressures.
A slight head space issue that is not increasing because of your current actions (firing hot loads) can be corrected by neck sizing. A more significant head space issue could result in too much brass being unsupported at the chamber mouth, and that can be dangerous.
You should also look for or have a gunsmith look for cracks in the area of the locking lugs, I haven't heard of this in the 788, but better save than sorry.

 

[kamikaze1a]

Finally got all the goods...case gage, chamber gages (go, no-go and field). Will post results later. Thanks everyone!