By Nathan Foster
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Matchgrade products and pricing here!
About MatchGrade Synthetic Stock Stabilizer
MatchGrade synthetic stock stabilizer is a product that has been specifically designed and tested by Terminal Ballistics Research Ltd in conjunction with a leading New Zealand polymer resin manufacturer. This product is designed to eliminate flexing in plastic synthetic rifle stocks to optimize accuracy.
For optimum accuracy, a rifle should always be bedded at the action and beginning of the barrel. Along with bedding, the barrel should always be free floated (not touching the stock forend). Nevertheless, regardless of efforts to free float the barrel, plastic rifle stocks often suffer forend flexing. In some instances, flexing will cause direct pressure against the rifle barrel, in other cases, the stress is indirect. In either case, these stresses upset barrel harmonics with a drastically negative effect on rifle accuracy.
Stock stabilizer is a light weight polymer resin, has a rich black color and a whipped cream like consistency. Besides re-enforcing plastic stocks, MatchGrade synthetic stock stabilizer can also be used for fill repairs and internal re-enforcement on fiberglass or carbon fiber stocks.
Stock stabilizer Instructions
You will need:
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Stock stabilizer part A and Part B
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MatchGrade release agent
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Masking tape
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Cling film (lunch wrap) or newspaper
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Plastercine (depending on fill type)
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Chisel, Dremmel or electric/air die grinder
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Sand paper
Mixing instructions for Stock stabilizer
Mix ratio 10 parts A to 1 part B
Approximate guide to synthetic stock filling weights
Synthetic sporter flat contour fill- 130 grams part A to 13 grams part B.
Synthetic sporter round contour fill- 150 grams part A to 15 grams part B.
Synthetic varmint/beaver tail flat contour fill- 180 grams part A to 18 grams part B.
Synthetic varmint/beaver tail round contour fill- 200 grams part A to 20 grams part B.
Using the supplied syringe
Immerse the syringe nozzle into the hardener (part B) and charge the syringe. Once the syringe is charged, eject the hardener back into the bottle (or dish). Recharge the syringe a second time to the desired measurement. This is important because the nozzle must be full (not just the syringe body) for a correct reading.
Clean up
Use vinegar (alkali) to clean equipment).
1. Job planning
MatchGrade synthetic stock stabilizer should always be utilized in conjunction with full bedding for optimum rifle accuracy. The job of stabilizing the stock can be done:
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Prior to bedding (easiest)
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At the same time as bedding
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After bedding
All plastic synthetic stocks feature an internal skeleton through the forend. The skeleton sits low in the stock so as not to interfere with the barrel. Stock stabilizer can be used to either:
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Fill the stock level with the top of this skeleton. The finish will be a flat surface. This type of fill is the lightest weight fill.
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Fill the stock using the rifle barrel as the mould shape. The finish will of course be round, slightly heavier than a basic 'flat fill' but is very strong. This type of fill can be very difficult to perform on Hogue stocks.
2. Stock preparation
Disassemble the rifle and put all small metal components into a suitable storage container. Once separated, the gunstock needs to be masked to protect it during the work process. It is best to use a layer of cling film or newspaper under the masking tape to minimize the amount of masking tape that actually contacts the stock. If a vice is to be used to hold the stock, ensure several layers of tape are put onto the stock where the vice jaws will be in contact. Be sure to remove any oil residues from within the stock using a degreaser (citrus based household degreasers work well)
Masking taped gun stock
The next step is to rough up and key into the stock work so that the compound can obtain good adhesion to the stock. On synthetic stocks it is imperative that 'mechanical locks' are created by cutting overhangs in the side walls of the stock. Use either a rotary die/air grinder or chisel for this work. If using a rotary grinder, tungsten deburring heads driven at low speeds are much more effective than stones or pollyrolls. The latter tend to produce too much heat, melt the plastic and become fouled and unable to cut within less than a minute.
Roughing up the stock forend. In the example above, the action is also being prepared for bedding at a later stage.
Once the stock is prepped, the various plans come into play.
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If a basic flat fill is to be used prior to full bedding, a Plastercine dam should be inserted where the recoil lug of the rifle action normally sits (beginning of the barrel).
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If the barrel is to be used as a mould prior to full bedding, the rifle barrel needs to be heavily masking taped to produce a measure of relief for free floating of the barrel. Following this, release agent should be applied to the masking tape.
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If the bedding and stabilizing are to done at the same time, the barrel should be heavily masked back to the balance point or barrel parallel as explained in the MatchGrade bedding compound instructions. The Bedding compound should be applied in such a way that it fills the action and barrel parallel and OVERLAPS the stock stabilizing compound. The barrel also needs to be heavily coated in release agent for ease of pulling the job which will have a huge adhesive contact area. A light coating of lee case lube on the barrel on top of the existing release agent can also help immensely.
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If the stock is to be stabilized after previous bedding work, a basic flat fill is the most suitable choice. Besides roughing up the plastic of the stock, it can also pay to undercut the previous barrel bedding slightly.
3. Mixing and applying stock stabilizer compound
MatchGrade synthetic stock stabilizer should be mixed at a ratio of 10 parts compound (part A) to 1 part hardener (part B). Mix thoroughly but try to avoid aggressive agitation (electric drills) which leads to air bubbling.
Apply the compound to the stock, carefully working the compound into each skeletal compartment. This product has an open time of well over two hours without excess heat so there is no need to rush. If performing a flat fill, wipe off excess compound from the upper inner sidewalls of the rifle with a clean rag. If using the barrel as a mould, after fitting the barrel in place, Masking tape the barrel in place ensuring that it sinks to the desired level. The surplus spilt over compound should be removed leaving only a very small bead at the edges of the barrel. If too much compound is removed, the compound may suck back and lose aesthetic appeal. Following this, apply masking tape along the barrel/stock channel to trap the bead of compound and so that the job can be handled without creating a mess.
Applying stabilizer compound. Swirl marks can be seen as a result of my working the compound into the skeletal sub frame of the stock.
4. Curing
On flat filled stocks, use either a heat lamp over the job or hot water bottles under or over the job. Wrap the job in blankets to trap heat.
If the barrel was used as a mould, the rifle should be turned upside down causing any air bubbles to rise away from the seen surfaces. Hot water bottles etc should be placed over the rifle and the whole job covered in blankets. The rifle must now be checked hourly to determine when the compound is tacking off to a soft toffee like consistency. Once the compound reaches this consistency, trim off the bead of compound along the barrel channel, flush with the top of the stock channel. Flat filled stocks can also be hand shaped at this time if there is any concern about the shape of the fill not forming as desired.
The job must now be left to post cure for at least 48 hours. During this time, hot water bottles should be swapped once cooled. The ideal post cure temperature for Both MatchGrade compounds is 40 degrees C for at least 48 hours however fluctuations in heat as the hot water bottles cool are acceptable. If the job is pulled or chiseled too early, the mixture will be hard but brittle. The same will occur in cooler weather if the job is left for 48 hours but without heat curing. Once the compound reaches full cure, it will be both hard and tough.
5. Finishing the job
Flat filled stocks will need very little attention once the compound has cured. Nevertheless, the rifle should be checked to see if the barrel is fully floating (not contacting the stock). If the job does not look as aesthetically pleasing as planned, the cured compound can be sanded and shaped to suit. That said, due to the fact that MatchGrade synthetic stock stabilizer is a lightweight product and lacks the density of our metal filled bedding compound, very small air bubbles/ pin holes will occur if the surface is sanded. Exposure of pinholes does not have any negative effects other than visual appearances- more of a concern to commercial gunsmiths. These small pinholes can either, be ignored, filled with more compound or even painted over.
With barrel molded fills, the barrel will need to be broken out. To do this, use a rubber mallet and strike the tape on the underside of the barrel until the parts separate. In lieu of a mallet, the job can be pried apart but this can require considerable effort- more so if the bedding was performed at the same time.
If the fill was performed prior to full bedding as a separate operation, the area at the barrel parallel should be roughed up again, in preparation for bedding. The top of the stock can be sanded at this stage or left until the full bedding job is complete. When sanding, start with 120 grit sand paper, working up to either 320 or 400 grit- both of these grit sizes will blend invisibly with the original stock finish.
Congratulations, you now have a stabilized, useful, life long, all weather synthetic stock.
Good shooting!
Flat fill on a client's Hogue stock. This job was lightly sanded to blend in the edges.
Matchgrade pricing
What is Rifle Bedding?
Rifle Bedding Instructions
Disclaimer/ WARNING: The views and opinions expressed in this article are solely those of the author and are not endorsed by any manufacturers. Terminal Ballistics Research and the author take no responsibility for the use or misuse of any views, opinions or information expressed in this article.
